<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2020 Workiva-->
<!--r:ffc3455b-541c-43d4-a53b-9ca1624f7e14,g:ccfe6bd9-1cf8-42d1-98de-94852a1d16aa-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/CoverPage" xlink:type="simple" xlink:href="cfb-20200930.xsd#CoverPage"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/CoverPage" xlink:type="extended" id="i032f9d44af6a406e9d51f5d4dc62add4_CoverPage"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/ConsolidatedBalanceSheets" xlink:type="simple" xlink:href="cfb-20200930.xsd#ConsolidatedBalanceSheets"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/ConsolidatedBalanceSheets" xlink:type="extended" id="i8fd6378f5d65448e97b92b165b6281a3_ConsolidatedBalanceSheets"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" xlink:href="cfb-20200930.xsd#ConsolidatedBalanceSheetsParenthetical"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended" id="i65d0ce6eef1d4f61b4e3d9f5ca4991b8_ConsolidatedBalanceSheetsParenthetical"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/ConsolidatedStatementsofIncomeUnaudited" xlink:type="simple" xlink:href="cfb-20200930.xsd#ConsolidatedStatementsofIncomeUnaudited"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/ConsolidatedStatementsofIncomeUnaudited" xlink:type="extended" id="ia49c5cf386e34286b9f277b32c1766ab_ConsolidatedStatementsofIncomeUnaudited">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_98cf6a31-840c-4932-9907-c89a850ab027" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestAndDividendIncomeOperatingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:to="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_98cf6a31-840c-4932-9907-c89a850ab027" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndFeeIncomeLoansAndLeases_474c8554-cecc-4bef-beba-bf12a60b4d8a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestAndFeeIncomeLoansAndLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_98cf6a31-840c-4932-9907-c89a850ab027" xlink:to="loc_us-gaap_InterestAndFeeIncomeLoansAndLeases_474c8554-cecc-4bef-beba-bf12a60b4d8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeSecuritiesTaxable_a0769cae-b73e-45e3-a2db-2507918fd591" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestIncomeSecuritiesTaxable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_98cf6a31-840c-4932-9907-c89a850ab027" xlink:to="loc_us-gaap_InterestIncomeSecuritiesTaxable_a0769cae-b73e-45e3-a2db-2507918fd591" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeSecuritiesTaxExempt_e5526bc7-0cd6-4982-86ef-ca11544135cb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestIncomeSecuritiesTaxExempt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_98cf6a31-840c-4932-9907-c89a850ab027" xlink:to="loc_us-gaap_InterestIncomeSecuritiesTaxExempt_e5526bc7-0cd6-4982-86ef-ca11544135cb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeDepositsWithFinancialInstitutions_e30ebf96-507f-4ccd-a73f-c8756e43d020" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestIncomeDepositsWithFinancialInstitutions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_98cf6a31-840c-4932-9907-c89a850ab027" xlink:to="loc_us-gaap_InterestIncomeDepositsWithFinancialInstitutions_e30ebf96-507f-4ccd-a73f-c8756e43d020" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendIncomeOperating_0b88e7a4-b65d-4b55-941f-52d4ad21c051" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendIncomeOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_98cf6a31-840c-4932-9907-c89a850ab027" xlink:to="loc_us-gaap_DividendIncomeOperating_0b88e7a4-b65d-4b55-941f-52d4ad21c051" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestAndDividendIncomeOperating_f7340861-488d-4dbe-aec7-591251434668" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestAndDividendIncomeOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestAndDividendIncomeOperatingAbstract_98cf6a31-840c-4932-9907-c89a850ab027" xlink:to="loc_us-gaap_InterestAndDividendIncomeOperating_f7340861-488d-4dbe-aec7-591251434668" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseAbstract_6f1076be-fb7e-40d7-9ee6-6207018a9da5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:to="loc_us-gaap_InterestExpenseAbstract_6f1076be-fb7e-40d7-9ee6-6207018a9da5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDeposits_8f8b0123-7157-4539-9d9c-73a20c74e4ae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseDeposits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_6f1076be-fb7e-40d7-9ee6-6207018a9da5" xlink:to="loc_us-gaap_InterestExpenseDeposits_8f8b0123-7157-4539-9d9c-73a20c74e4ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchase_b4b1668c-98c8-4553-9f84-d31a44c2a80d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchase"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_6f1076be-fb7e-40d7-9ee6-6207018a9da5" xlink:to="loc_us-gaap_InterestExpenseFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchase_b4b1668c-98c8-4553-9f84-d31a44c2a80d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesShortTerm_ee38c2aa-ca54-4d8b-9e5e-cfd7a216a840" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesShortTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_6f1076be-fb7e-40d7-9ee6-6207018a9da5" xlink:to="loc_us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesShortTerm_ee38c2aa-ca54-4d8b-9e5e-cfd7a216a840" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseOtherShortTermBorrowings_9512d4df-c5f5-40ac-9bc5-dc6c0f13a77d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseOtherShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_6f1076be-fb7e-40d7-9ee6-6207018a9da5" xlink:to="loc_us-gaap_InterestExpenseOtherShortTermBorrowings_9512d4df-c5f5-40ac-9bc5-dc6c0f13a77d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_61cede90-3b09-4f5e-9ca9-e0fa6eedd92e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InterestExpenseAbstract_6f1076be-fb7e-40d7-9ee6-6207018a9da5" xlink:to="loc_us-gaap_InterestExpense_61cede90-3b09-4f5e-9ca9-e0fa6eedd92e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_89052125-4e90-49ac-9cc5-354ec4553a9e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_89052125-4e90-49ac-9cc5-354ec4553a9e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForLoanLossesExpensed_8ab7d492-822b-456d-a046-8f19e058596f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProvisionForLoanLossesExpensed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:to="loc_us-gaap_ProvisionForLoanLossesExpensed_8ab7d492-822b-456d-a046-8f19e058596f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_2b5ce7d0-40e7-44f4-abd0-855a42e3ee05" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:to="loc_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_2b5ce7d0-40e7-44f4-abd0-855a42e3ee05" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncomeAbstract_e8db547e-82a4-476e-9116-f1c5cd8a862d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoninterestIncomeAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:to="loc_us-gaap_NoninterestIncomeAbstract_e8db547e-82a4-476e-9116-f1c5cd8a862d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_8f6ac606-0e01-4483-a67e-1861e654b22e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_e8db547e-82a4-476e-9116-f1c5cd8a862d" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_8f6ac606-0e01-4483-a67e-1861e654b22e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnInvestments_91952672-8aec-45f2-889c-ff5d513e1d8b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainLossOnInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_e8db547e-82a4-476e-9116-f1c5cd8a862d" xlink:to="loc_us-gaap_GainLossOnInvestments_91952672-8aec-45f2-889c-ff5d513e1d8b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf_bf9b25df-c706-4c66-beb0-762243121f6a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_e8db547e-82a4-476e-9116-f1c5cd8a862d" xlink:to="loc_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf_bf9b25df-c706-4c66-beb0-762243121f6a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSalesOfLoansNet_3206a4e8-8673-4879-bb0e-c139b9f16d67" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainLossOnSalesOfLoansNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_e8db547e-82a4-476e-9116-f1c5cd8a862d" xlink:to="loc_us-gaap_GainLossOnSalesOfLoansNet_3206a4e8-8673-4879-bb0e-c139b9f16d67" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BankOwnedLifeInsuranceIncome_8412da24-61ca-43e7-a563-1c8ca62ee18a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BankOwnedLifeInsuranceIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_e8db547e-82a4-476e-9116-f1c5cd8a862d" xlink:to="loc_us-gaap_BankOwnedLifeInsuranceIncome_8412da24-61ca-43e7-a563-1c8ca62ee18a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_7ee57d8b-e1a0-479c-bc18-6a1aa1a554ec" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainLossOnDerivativeInstrumentsNetPretax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_e8db547e-82a4-476e-9116-f1c5cd8a862d" xlink:to="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_7ee57d8b-e1a0-479c-bc18-6a1aa1a554ec" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncomeOtherOperatingIncome_c50b30d6-a528-4b3e-8922-c8a807ff2a2b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoninterestIncomeOtherOperatingIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_e8db547e-82a4-476e-9116-f1c5cd8a862d" xlink:to="loc_us-gaap_NoninterestIncomeOtherOperatingIncome_c50b30d6-a528-4b3e-8922-c8a807ff2a2b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestIncome_5f517aa6-b708-4e5e-9e24-7e0f9cb0c3d3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoninterestIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestIncomeAbstract_e8db547e-82a4-476e-9116-f1c5cd8a862d" xlink:to="loc_us-gaap_NoninterestIncome_5f517aa6-b708-4e5e-9e24-7e0f9cb0c3d3" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestExpenseAbstract_fc7e61f1-4efb-4275-9ea4-e3521a7cd7f2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoninterestExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:to="loc_us-gaap_NoninterestExpenseAbstract_fc7e61f1-4efb-4275-9ea4-e3521a7cd7f2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LaborAndRelatedExpense_1280e0e4-8f05-4e70-abb8-64b6e5d16bbb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LaborAndRelatedExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_fc7e61f1-4efb-4275-9ea4-e3521a7cd7f2" xlink:to="loc_us-gaap_LaborAndRelatedExpense_1280e0e4-8f05-4e70-abb8-64b6e5d16bbb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OccupancyNet_5ef17e5e-ca9d-44af-bff3-a707f5692253" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OccupancyNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_fc7e61f1-4efb-4275-9ea4-e3521a7cd7f2" xlink:to="loc_us-gaap_OccupancyNet_5ef17e5e-ca9d-44af-bff3-a707f5692253" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfessionalFees_6f2d0b77-741c-4636-88b4-4a65251fedb2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProfessionalFees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_fc7e61f1-4efb-4275-9ea4-e3521a7cd7f2" xlink:to="loc_us-gaap_ProfessionalFees_6f2d0b77-741c-4636-88b4-4a65251fedb2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalDepositInsuranceCorporationPremiumExpense_74169988-c7f5-4cb0-a92b-c24502698c7e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FederalDepositInsuranceCorporationPremiumExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_fc7e61f1-4efb-4275-9ea4-e3521a7cd7f2" xlink:to="loc_us-gaap_FederalDepositInsuranceCorporationPremiumExpense_74169988-c7f5-4cb0-a92b-c24502698c7e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InformationTechnologyAndDataProcessing_38c0ffd8-5a2e-4b88-b3be-26df25238dd0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InformationTechnologyAndDataProcessing"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_fc7e61f1-4efb-4275-9ea4-e3521a7cd7f2" xlink:to="loc_us-gaap_InformationTechnologyAndDataProcessing_38c0ffd8-5a2e-4b88-b3be-26df25238dd0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdvertisingExpense_6915c8e0-f18d-47c0-9896-0140efda0f31" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdvertisingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_fc7e61f1-4efb-4275-9ea4-e3521a7cd7f2" xlink:to="loc_us-gaap_AdvertisingExpense_6915c8e0-f18d-47c0-9896-0140efda0f31" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Communication_c7792e66-ce6d-4bff-8bb0-452cf087e710" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Communication"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_fc7e61f1-4efb-4275-9ea4-e3521a7cd7f2" xlink:to="loc_us-gaap_Communication_c7792e66-ce6d-4bff-8bb0-452cf087e710" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeclosedRealEstateExpense_7971a836-5937-4a68-8032-f8583c89e186" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ForeclosedRealEstateExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_fc7e61f1-4efb-4275-9ea4-e3521a7cd7f2" xlink:to="loc_us-gaap_ForeclosedRealEstateExpense_7971a836-5937-4a68-8032-f8583c89e186" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_688f8380-4541-4057-a50e-3d9ed21476a0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_fc7e61f1-4efb-4275-9ea4-e3521a7cd7f2" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_688f8380-4541-4057-a50e-3d9ed21476a0" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoninterestExpense_5fcf5033-906f-4195-9a64-5c2e5d402fdb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherNoninterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_fc7e61f1-4efb-4275-9ea4-e3521a7cd7f2" xlink:to="loc_us-gaap_OtherNoninterestExpense_5fcf5033-906f-4195-9a64-5c2e5d402fdb" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoninterestExpense_c29893cd-d10d-45ec-b28f-145600e8acf5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoninterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NoninterestExpenseAbstract_fc7e61f1-4efb-4275-9ea4-e3521a7cd7f2" xlink:to="loc_us-gaap_NoninterestExpense_c29893cd-d10d-45ec-b28f-145600e8acf5" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossAttributableToParent_1569fc75-851b-433b-8eca-eed789e02645" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:to="loc_us-gaap_IncomeLossAttributableToParent_1569fc75-851b-433b-8eca-eed789e02645" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_35a91942-b016-43bb-9ea6-916535b6714a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_35a91942-b016-43bb-9ea6-916535b6714a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_ada577e8-f3a0-4dea-9e31-c8b06adf0d06" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:to="loc_us-gaap_NetIncomeLoss_ada577e8-f3a0-4dea-9e31-c8b06adf0d06" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_84d3c0bc-df63-4a0a-be34-9c89d89c3916" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:to="loc_us-gaap_EarningsPerShareBasic_84d3c0bc-df63-4a0a-be34-9c89d89c3916" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_cce22aad-d3e8-489a-81fa-6491b1f5b3f0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:to="loc_us-gaap_EarningsPerShareDiluted_cce22aad-d3e8-489a-81fa-6491b1f5b3f0" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_c0c6b1c8-38fc-4050-be7f-7ae309938715" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_02b7d504-06c7-4c81-9c4a-82024d3bbadc" xlink:to="loc_us-gaap_StatementTable_c0c6b1c8-38fc-4050-be7f-7ae309938715" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_0412a0b9-052f-43a1-af20-e63cac435b4c" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_c0c6b1c8-38fc-4050-be7f-7ae309938715" xlink:to="loc_srt_ProductOrServiceAxis_0412a0b9-052f-43a1-af20-e63cac435b4c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_0412a0b9-052f-43a1-af20-e63cac435b4c_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_0412a0b9-052f-43a1-af20-e63cac435b4c" xlink:to="loc_srt_ProductsAndServicesDomain_0412a0b9-052f-43a1-af20-e63cac435b4c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_941f48a5-3085-410d-a89b-16224a5a5bc3" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_0412a0b9-052f-43a1-af20-e63cac435b4c" xlink:to="loc_srt_ProductsAndServicesDomain_941f48a5-3085-410d-a89b-16224a5a5bc3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ServiceChargesAndFeesMember_94901849-76b0-481a-95df-4e84effe6301" xlink:href="cfb-20200930.xsd#cfb_ServiceChargesAndFeesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_941f48a5-3085-410d-a89b-16224a5a5bc3" xlink:to="loc_cfb_ServiceChargesAndFeesMember_94901849-76b0-481a-95df-4e84effe6301" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ATMAndCreditCardInterchangeIncomeMember_9f4faa6d-da09-48e9-a0df-1b87a2aed810" xlink:href="cfb-20200930.xsd#cfb_ATMAndCreditCardInterchangeIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_941f48a5-3085-410d-a89b-16224a5a5bc3" xlink:to="loc_cfb_ATMAndCreditCardInterchangeIncomeMember_9f4faa6d-da09-48e9-a0df-1b87a2aed810" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/ConsolidatedStatementsofComprehensiveIncomeUnaudited" xlink:type="simple" xlink:href="cfb-20200930.xsd#ConsolidatedStatementsofComprehensiveIncomeUnaudited"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/ConsolidatedStatementsofComprehensiveIncomeUnaudited" xlink:type="extended" id="if2706593c28a454e98ecfc581c64c196_ConsolidatedStatementsofComprehensiveIncomeUnaudited"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/ConsolidatedStatementsofStockholdersEquityUnaudited" xlink:type="simple" xlink:href="cfb-20200930.xsd#ConsolidatedStatementsofStockholdersEquityUnaudited"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/ConsolidatedStatementsofStockholdersEquityUnaudited" xlink:type="extended" id="i5c59391c9ab44f5081d104514babff47_ConsolidatedStatementsofStockholdersEquityUnaudited">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_f45adc2c-63cc-44fd-b221-988fb85ba7b3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_f45adc2c-63cc-44fd-b221-988fb85ba7b3" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_b3b2f643-7f94-4ada-9609-4afac21aae30" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_us-gaap_SharesOutstanding_b3b2f643-7f94-4ada-9609-4afac21aae30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_8cf5dece-99e1-4630-8dff-73c748ff2fbb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_us-gaap_StockholdersEquity_8cf5dece-99e1-4630-8dff-73c748ff2fbb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_4bb41d09-3383-48f7-920e-9b9ce26b8dd2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_us-gaap_NetIncomeLoss_4bb41d09-3383-48f7-920e-9b9ce26b8dd2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_afc9fa83-e586-4c8c-b14a-ef1e63343de0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_afc9fa83-e586-4c8c-b14a-ef1e63343de0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_d88ebad4-53c9-4258-9184-2306b431cde1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_d88ebad4-53c9-4258-9184-2306b431cde1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_ec40e988-e8f4-4dc1-9238-8bb72484ba7d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_ec40e988-e8f4-4dc1-9238-8bb72484ba7d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_67de6cc1-6f43-4d98-86d3-6cafc5acef9b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_67de6cc1-6f43-4d98-86d3-6cafc5acef9b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_8627a11f-2342-4e35-9c0a-4f8acb7b60b7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_8627a11f-2342-4e35-9c0a-4f8acb7b60b7" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_77333e4c-8d78-40fe-8307-c87b800b364a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_77333e4c-8d78-40fe-8307-c87b800b364a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_2ab70cf5-2422-45bb-8989-c80815ca611f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_2ab70cf5-2422-45bb-8989-c80815ca611f" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPreferredStockCash_fdc2a688-afc6-4f8f-bd2a-64f4e20ad34a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendsPreferredStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_us-gaap_DividendsPreferredStockCash_fdc2a688-afc6-4f8f-bd2a-64f4e20ad34a" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_AdjustmentsToAdditionalPaidInCapitalEmployeeReceivablesFromSaleOfStock_45a89c6c-9368-417a-8821-1c33f40dd424" xlink:href="cfb-20200930.xsd#cfb_AdjustmentsToAdditionalPaidInCapitalEmployeeReceivablesFromSaleOfStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_cfb_AdjustmentsToAdditionalPaidInCapitalEmployeeReceivablesFromSaleOfStock_45a89c6c-9368-417a-8821-1c33f40dd424" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_64dadd57-8302-4776-aefd-f0b61b80e9c1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_64dadd57-8302-4776-aefd-f0b61b80e9c1" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition_07b92586-7423-4b9a-a9da-8a152702ddc4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_1d5ad45d-44ab-43d5-abc3-b053e85f6b93" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition_07b92586-7423-4b9a-a9da-8a152702ddc4" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_7a864b60-b885-439e-8623-2a7b0f41fe08" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_1b57b5ef-6ead-42b1-8c7e-940cae282442" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_3291b00e-a864-4855-a592-b5865e307f25" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_f45adc2c-63cc-44fd-b221-988fb85ba7b3" xlink:to="loc_us-gaap_StatementTable_3291b00e-a864-4855-a592-b5865e307f25" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_f3063451-cac1-4a88-999c-8a50566d0dd8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_3291b00e-a864-4855-a592-b5865e307f25" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_f3063451-cac1-4a88-999c-8a50566d0dd8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_f3063451-cac1-4a88-999c-8a50566d0dd8_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_f3063451-cac1-4a88-999c-8a50566d0dd8" xlink:to="loc_us-gaap_EquityComponentDomain_f3063451-cac1-4a88-999c-8a50566d0dd8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_db4ce0c8-9495-4e45-ba10-29f32940fa02" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_f3063451-cac1-4a88-999c-8a50566d0dd8" xlink:to="loc_us-gaap_EquityComponentDomain_db4ce0c8-9495-4e45-ba10-29f32940fa02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_d1515d6f-7126-4256-a449-6bdb69061271" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_db4ce0c8-9495-4e45-ba10-29f32940fa02" xlink:to="loc_us-gaap_PreferredStockMember_d1515d6f-7126-4256-a449-6bdb69061271" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_8423aaea-8e50-4e34-ad5a-949a0fdd75e9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_db4ce0c8-9495-4e45-ba10-29f32940fa02" xlink:to="loc_us-gaap_CommonStockMember_8423aaea-8e50-4e34-ad5a-949a0fdd75e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_f6d1fe33-88c4-40ec-b9f3-00929328d93c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_db4ce0c8-9495-4e45-ba10-29f32940fa02" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_f6d1fe33-88c4-40ec-b9f3-00929328d93c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_070dfbcf-8df4-43cd-96ac-05ea7d57c27a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_db4ce0c8-9495-4e45-ba10-29f32940fa02" xlink:to="loc_us-gaap_RetainedEarningsMember_070dfbcf-8df4-43cd-96ac-05ea7d57c27a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_09739896-8c68-4005-bae8-639686c820d4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_db4ce0c8-9495-4e45-ba10-29f32940fa02" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_09739896-8c68-4005-bae8-639686c820d4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_a6c9803a-d5ae-4e09-817a-988db82fa4b2" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_3291b00e-a864-4855-a592-b5865e307f25" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_a6c9803a-d5ae-4e09-817a-988db82fa4b2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_a6c9803a-d5ae-4e09-817a-988db82fa4b2_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_a6c9803a-d5ae-4e09-817a-988db82fa4b2" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_a6c9803a-d5ae-4e09-817a-988db82fa4b2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_1f85e906-c585-4927-a506-d0fd5ef48578" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_a6c9803a-d5ae-4e09-817a-988db82fa4b2" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_1f85e906-c585-4927-a506-d0fd5ef48578" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_a0204128-ca12-40e3-8899-8a7785571138" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_1f85e906-c585-4927-a506-d0fd5ef48578" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_a0204128-ca12-40e3-8899-8a7785571138" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_b63ff5fb-e0a0-41f5-8468-e3ff62d5ca4c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_3291b00e-a864-4855-a592-b5865e307f25" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_b63ff5fb-e0a0-41f5-8468-e3ff62d5ca4c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_b63ff5fb-e0a0-41f5-8468-e3ff62d5ca4c_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_b63ff5fb-e0a0-41f5-8468-e3ff62d5ca4c" xlink:to="loc_us-gaap_TypeOfAdoptionMember_b63ff5fb-e0a0-41f5-8468-e3ff62d5ca4c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_c16eb222-1840-4ed4-8796-e5e528539a1c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_b63ff5fb-e0a0-41f5-8468-e3ff62d5ca4c" xlink:to="loc_us-gaap_TypeOfAdoptionMember_c16eb222-1840-4ed4-8796-e5e528539a1c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate201601Member_4fb2dda1-9f06-4e2e-81a3-c12965d7d838" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountingStandardsUpdate201601Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_c16eb222-1840-4ed4-8796-e5e528539a1c" xlink:to="loc_us-gaap_AccountingStandardsUpdate201601Member_4fb2dda1-9f06-4e2e-81a3-c12965d7d838" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate201807Member_46ab3977-a1e6-46c8-97fd-8bad82c19b1b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountingStandardsUpdate201807Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_c16eb222-1840-4ed4-8796-e5e528539a1c" xlink:to="loc_us-gaap_AccountingStandardsUpdate201807Member_46ab3977-a1e6-46c8-97fd-8bad82c19b1b" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/ConsolidatedStatementsofCashFlowsUnaudited" xlink:type="simple" xlink:href="cfb-20200930.xsd#ConsolidatedStatementsofCashFlowsUnaudited"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/ConsolidatedStatementsofCashFlowsUnaudited" xlink:type="extended" id="ia032113bce244127b92e14d86eced3f3_ConsolidatedStatementsofCashFlowsUnaudited"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/NatureofOperationsandSummaryofSignificantAccountingPolicies" xlink:type="simple" xlink:href="cfb-20200930.xsd#NatureofOperationsandSummaryofSignificantAccountingPolicies"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/NatureofOperationsandSummaryofSignificantAccountingPolicies" xlink:type="extended" id="i3e7a9a8fa6f74ac581913c03ebf04e7f_NatureofOperationsandSummaryofSignificantAccountingPolicies"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/NatureofOperationsandSummaryofSignificantAccountingPoliciesPolicies" xlink:type="simple" xlink:href="cfb-20200930.xsd#NatureofOperationsandSummaryofSignificantAccountingPoliciesPolicies"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/NatureofOperationsandSummaryofSignificantAccountingPoliciesPolicies" xlink:type="extended" id="i6fc3394a70ae4b87b3b4258e93c40b94_NatureofOperationsandSummaryofSignificantAccountingPoliciesPolicies"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/NatureofOperationsandSummaryofSignificantAccountingPoliciesTables" xlink:type="simple" xlink:href="cfb-20200930.xsd#NatureofOperationsandSummaryofSignificantAccountingPoliciesTables"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/NatureofOperationsandSummaryofSignificantAccountingPoliciesTables" xlink:type="extended" id="idd5db557b2e646cc928db9b1a8e73271_NatureofOperationsandSummaryofSignificantAccountingPoliciesTables"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/NatureofOperationsandSummaryofSignificantAccountingPoliciesDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#NatureofOperationsandSummaryofSignificantAccountingPoliciesDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/NatureofOperationsandSummaryofSignificantAccountingPoliciesDetails" xlink:type="extended" id="ie42c5f1612184e29ba7c30f7c63f0adb_NatureofOperationsandSummaryofSignificantAccountingPoliciesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_0c773f49-2e2e-465c-97af-f4b08d489b09" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndSecuritiesSegregatedUnderFederalAndOtherRegulations_40b1a196-1bea-43a2-84e4-ca535c8887a0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndSecuritiesSegregatedUnderFederalAndOtherRegulations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_0c773f49-2e2e-465c-97af-f4b08d489b09" xlink:to="loc_us-gaap_CashAndSecuritiesSegregatedUnderFederalAndOtherRegulations_40b1a196-1bea-43a2-84e4-ca535c8887a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashReserveDepositRequiredAndMade_2de4396d-66ff-4e5b-b467-a9fcc028e8e7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashReserveDepositRequiredAndMade"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_0c773f49-2e2e-465c-97af-f4b08d489b09" xlink:to="loc_us-gaap_CashReserveDepositRequiredAndMade_2de4396d-66ff-4e5b-b467-a9fcc028e8e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableGross_c2033ce1-c8ed-43a3-9f64-7e539968cd99" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesReceivableGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_0c773f49-2e2e-465c-97af-f4b08d489b09" xlink:to="loc_us-gaap_NotesReceivableGross_c2033ce1-c8ed-43a3-9f64-7e539968cd99" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableWithVariableRatesOfInterest1_c4c8999b-2df9-46e8-8613-cd970db1c580" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoansReceivableWithVariableRatesOfInterest1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_0c773f49-2e2e-465c-97af-f4b08d489b09" xlink:to="loc_us-gaap_LoansReceivableWithVariableRatesOfInterest1_c4c8999b-2df9-46e8-8613-cd970db1c580" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_8c290a78-81ea-4f77-9f51-1302e0144da6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_0c773f49-2e2e-465c-97af-f4b08d489b09" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_8c290a78-81ea-4f77-9f51-1302e0144da6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_27b9c61f-fb88-495b-b7df-f5cf075b8960" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_8c290a78-81ea-4f77-9f51-1302e0144da6" xlink:to="loc_us-gaap_VariableRateAxis_27b9c61f-fb88-495b-b7df-f5cf075b8960" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_27b9c61f-fb88-495b-b7df-f5cf075b8960_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_27b9c61f-fb88-495b-b7df-f5cf075b8960" xlink:to="loc_us-gaap_VariableRateDomain_27b9c61f-fb88-495b-b7df-f5cf075b8960_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_a3a199f3-a923-4e71-80b4-b155992c44e1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_27b9c61f-fb88-495b-b7df-f5cf075b8960" xlink:to="loc_us-gaap_VariableRateDomain_a3a199f3-a923-4e71-80b4-b155992c44e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_2de2a9fe-f83b-42d2-9ade-9c3efa8f2411" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_a3a199f3-a923-4e71-80b4-b155992c44e1" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_2de2a9fe-f83b-42d2-9ade-9c3efa8f2411" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_05d9a4ae-c787-4610-9b32-9b53768e31b0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_8c290a78-81ea-4f77-9f51-1302e0144da6" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_05d9a4ae-c787-4610-9b32-9b53768e31b0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_05d9a4ae-c787-4610-9b32-9b53768e31b0_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_05d9a4ae-c787-4610-9b32-9b53768e31b0" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_05d9a4ae-c787-4610-9b32-9b53768e31b0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_778abd38-91ff-4493-b7e1-c9d7234d875d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_05d9a4ae-c787-4610-9b32-9b53768e31b0" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_778abd38-91ff-4493-b7e1-c9d7234d875d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformingFinancingReceivableMember_a802b85b-7e58-49d0-b37d-e9fdeab698ab" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PerformingFinancingReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_778abd38-91ff-4493-b7e1-c9d7234d875d" xlink:to="loc_us-gaap_PerformingFinancingReceivableMember_a802b85b-7e58-49d0-b37d-e9fdeab698ab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentAxis_d20babe8-8127-42d7-9e84-e4ff3f3b8869" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InternalCreditAssessmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_8c290a78-81ea-4f77-9f51-1302e0144da6" xlink:to="loc_us-gaap_InternalCreditAssessmentAxis_d20babe8-8127-42d7-9e84-e4ff3f3b8869" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_d20babe8-8127-42d7-9e84-e4ff3f3b8869_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_d20babe8-8127-42d7-9e84-e4ff3f3b8869" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_d20babe8-8127-42d7-9e84-e4ff3f3b8869_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_22886f0c-f83a-4dbf-b625-249a6d50b9ea" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_d20babe8-8127-42d7-9e84-e4ff3f3b8869" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_22886f0c-f83a-4dbf-b625-249a6d50b9ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubstandardMember_83e635b5-8519-421e-9f1c-2f08077b9db3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubstandardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_22886f0c-f83a-4dbf-b625-249a6d50b9ea" xlink:to="loc_us-gaap_SubstandardMember_83e635b5-8519-421e-9f1c-2f08077b9db3" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/EarningsPerShare" xlink:type="simple" xlink:href="cfb-20200930.xsd#EarningsPerShare"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/EarningsPerShare" xlink:type="extended" id="i057cffb118f54b66a5a4ea32dfd84813_EarningsPerShare"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/EarningsPerShareTables" xlink:type="simple" xlink:href="cfb-20200930.xsd#EarningsPerShareTables"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/EarningsPerShareTables" xlink:type="extended" id="i33f5fdc45f7e45e7885acccdb946e751_EarningsPerShareTables"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/EarningsPerShareDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#EarningsPerShareDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/EarningsPerShareDetails" xlink:type="extended" id="i32ce025d746047af86efd86e2c9ffc76_EarningsPerShareDetails"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/Securities" xlink:type="simple" xlink:href="cfb-20200930.xsd#Securities"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/Securities" xlink:type="extended" id="id0a7bc1b2c1a433d90d8347391b927f1_Securities"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/SecuritiesTables" xlink:type="simple" xlink:href="cfb-20200930.xsd#SecuritiesTables"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/SecuritiesTables" xlink:type="extended" id="i589a90ac620f44c69c487326c4abca78_SecuritiesTables"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/SecuritiesAmortizedCostandFairValueofSecuritiesDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#SecuritiesAmortizedCostandFairValueofSecuritiesDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/SecuritiesAmortizedCostandFairValueofSecuritiesDetails" xlink:type="extended" id="i3effa330f2c04fd0ae4e0dae4770aaed_SecuritiesAmortizedCostandFairValueofSecuritiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems_f56bdb8d-49c2-4de0-b05f-9affd0dd9bef" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesAbstract_f76b5902-52e8-4216-a243-a89b198d5e75" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems_f56bdb8d-49c2-4de0-b05f-9affd0dd9bef" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesAbstract_f76b5902-52e8-4216-a243-a89b198d5e75" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_2bf1b544-8542-4db3-9d5d-2045af926a84" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_f76b5902-52e8-4216-a243-a89b198d5e75" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_2bf1b544-8542-4db3-9d5d-2045af926a84" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_828c8d5e-9455-4fc5-b7e3-7ad71a668c74" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_f76b5902-52e8-4216-a243-a89b198d5e75" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_828c8d5e-9455-4fc5-b7e3-7ad71a668c74" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_9fa03bf9-4016-4ca8-805e-398275a7e755" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_f76b5902-52e8-4216-a243-a89b198d5e75" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_9fa03bf9-4016-4ca8-805e-398275a7e755" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_4e099a41-07e3-46e9-9221-d1c119a18062" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_f76b5902-52e8-4216-a243-a89b198d5e75" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_4e099a41-07e3-46e9-9221-d1c119a18062" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiGainLossAbstract_f9e3123e-b19b-49f1-8ce7-e4637469578f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquitySecuritiesFvNiGainLossAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems_f56bdb8d-49c2-4de0-b05f-9affd0dd9bef" xlink:to="loc_us-gaap_EquitySecuritiesFvNiGainLossAbstract_f9e3123e-b19b-49f1-8ce7-e4637469578f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiCost_b4c4d600-fb10-4053-a424-fe14c89e7f34" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquitySecuritiesFvNiCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquitySecuritiesFvNiGainLossAbstract_f9e3123e-b19b-49f1-8ce7-e4637469578f" xlink:to="loc_us-gaap_EquitySecuritiesFvNiCost_b4c4d600-fb10-4053-a424-fe14c89e7f34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_EquitySecuritiesFVNIAccumulatedGrossUnrealizedGain_a7ccc0ec-6879-4ef4-87d0-58c0747ab8d2" xlink:href="cfb-20200930.xsd#cfb_EquitySecuritiesFVNIAccumulatedGrossUnrealizedGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquitySecuritiesFvNiGainLossAbstract_f9e3123e-b19b-49f1-8ce7-e4637469578f" xlink:to="loc_cfb_EquitySecuritiesFVNIAccumulatedGrossUnrealizedGain_a7ccc0ec-6879-4ef4-87d0-58c0747ab8d2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_EquitySecuritiesFVNIAccumulatedGrossUnrealizedLoss_9bbfbb86-899b-4997-884b-c63e19e3e649" xlink:href="cfb-20200930.xsd#cfb_EquitySecuritiesFVNIAccumulatedGrossUnrealizedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquitySecuritiesFvNiGainLossAbstract_f9e3123e-b19b-49f1-8ce7-e4637469578f" xlink:to="loc_cfb_EquitySecuritiesFVNIAccumulatedGrossUnrealizedLoss_9bbfbb86-899b-4997-884b-c63e19e3e649" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNi_c338a0a1-1d17-4abd-adf6-6c572b967970" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquitySecuritiesFvNi"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquitySecuritiesFvNiGainLossAbstract_f9e3123e-b19b-49f1-8ce7-e4637469578f" xlink:to="loc_us-gaap_EquitySecuritiesFvNi_c338a0a1-1d17-4abd-adf6-6c572b967970" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesTradingAndEquitySecuritiesFvNiAbstract_62498dc8-b601-496b-b814-485ef7a63010" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesTradingAndEquitySecuritiesFvNiAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems_f56bdb8d-49c2-4de0-b05f-9affd0dd9bef" xlink:to="loc_us-gaap_DebtSecuritiesTradingAndEquitySecuritiesFvNiAbstract_62498dc8-b601-496b-b814-485ef7a63010" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNIAmortizedCost_1a4fc0a0-8915-45a3-bef7-f3ba43e20565" xlink:href="cfb-20200930.xsd#cfb_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNIAmortizedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesTradingAndEquitySecuritiesFvNiAbstract_62498dc8-b601-496b-b814-485ef7a63010" xlink:to="loc_cfb_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNIAmortizedCost_1a4fc0a0-8915-45a3-bef7-f3ba43e20565" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNIAccumulatedGrossUnrealizedGain_c4aec5e1-8a9c-4820-8ad0-f001cacceaff" xlink:href="cfb-20200930.xsd#cfb_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNIAccumulatedGrossUnrealizedGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesTradingAndEquitySecuritiesFvNiAbstract_62498dc8-b601-496b-b814-485ef7a63010" xlink:to="loc_cfb_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNIAccumulatedGrossUnrealizedGain_c4aec5e1-8a9c-4820-8ad0-f001cacceaff" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNIAccumulatedGrossUnrealizedLoss_968edbba-6458-450c-9518-7fa0bfb53086" xlink:href="cfb-20200930.xsd#cfb_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNIAccumulatedGrossUnrealizedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesTradingAndEquitySecuritiesFvNiAbstract_62498dc8-b601-496b-b814-485ef7a63010" xlink:to="loc_cfb_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNIAccumulatedGrossUnrealizedLoss_968edbba-6458-450c-9518-7fa0bfb53086" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNI_14915cbb-45fa-4c52-b45a-8bcb00ca60b1" xlink:href="cfb-20200930.xsd#cfb_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNI"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesTradingAndEquitySecuritiesFvNiAbstract_62498dc8-b601-496b-b814-485ef7a63010" xlink:to="loc_cfb_DebtSecuritiesAvailableForSaleAndEquitySecuritiesFVNI_14915cbb-45fa-4c52-b45a-8bcb00ca60b1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable_c0e55506-8cc6-42ef-a477-8a2495a24cd9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems_f56bdb8d-49c2-4de0-b05f-9affd0dd9bef" xlink:to="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable_c0e55506-8cc6-42ef-a477-8a2495a24cd9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_f5219d01-b862-4a01-9172-79410834b956" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable_c0e55506-8cc6-42ef-a477-8a2495a24cd9" xlink:to="loc_us-gaap_FinancialInstrumentAxis_f5219d01-b862-4a01-9172-79410834b956" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_f5219d01-b862-4a01-9172-79410834b956_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_f5219d01-b862-4a01-9172-79410834b956" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_f5219d01-b862-4a01-9172-79410834b956_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_70a45afe-2d32-441f-b75e-5867f1c9742d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_f5219d01-b862-4a01-9172-79410834b956" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_70a45afe-2d32-441f-b75e-5867f1c9742d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_eb427b0d-f52a-4f7c-93ef-4acd292f37d6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_70a45afe-2d32-441f-b75e-5867f1c9742d" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_eb427b0d-f52a-4f7c-93ef-4acd292f37d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_CollateralizedMortgageObligationsGovernmentSponsoredEntitiesMember_3e9a68cb-6869-4b8b-9cd3-25b6e973ab3a" xlink:href="cfb-20200930.xsd#cfb_CollateralizedMortgageObligationsGovernmentSponsoredEntitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_70a45afe-2d32-441f-b75e-5867f1c9742d" xlink:to="loc_cfb_CollateralizedMortgageObligationsGovernmentSponsoredEntitiesMember_3e9a68cb-6869-4b8b-9cd3-25b6e973ab3a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_518e119b-da90-453d-b084-1eaa2e97ba1b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_70a45afe-2d32-441f-b75e-5867f1c9742d" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_518e119b-da90-453d-b084-1eaa2e97ba1b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateBondSecuritiesMember_1804f6ef-7cb9-4b2f-ace9-d8c3d6bfdc0d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateBondSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_70a45afe-2d32-441f-b75e-5867f1c9742d" xlink:to="loc_us-gaap_CorporateBondSecuritiesMember_1804f6ef-7cb9-4b2f-ace9-d8c3d6bfdc0d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MutualFundMember_bff203a7-492c-4815-83ab-9959a3a07ce9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MutualFundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_70a45afe-2d32-441f-b75e-5867f1c9742d" xlink:to="loc_us-gaap_MutualFundMember_bff203a7-492c-4815-83ab-9959a3a07ce9" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/SecuritiesAmortizedCostandFairValuebyMaturityDateDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#SecuritiesAmortizedCostandFairValuebyMaturityDateDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/SecuritiesAmortizedCostandFairValuebyMaturityDateDetails" xlink:type="extended" id="id6c85b5af7cc4b6890d7d8bef6d31d6b_SecuritiesAmortizedCostandFairValuebyMaturityDateDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_86a4684e-79e3-4b6d-a923-d445ee58adce" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostBasisRollingMaturityAbstract_219635e7-5059-4f82-a032-c8b076d1e744" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostBasisRollingMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_86a4684e-79e3-4b6d-a923-d445ee58adce" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostBasisRollingMaturityAbstract_219635e7-5059-4f82-a032-c8b076d1e744" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis_34fd441d-a4e5-41c3-8871-8c1c8ca2d45f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostBasisRollingMaturityAbstract_219635e7-5059-4f82-a032-c8b076d1e744" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis_34fd441d-a4e5-41c3-8871-8c1c8ca2d45f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis_62d2f607-d45e-44df-89f7-23a91e31f022" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostBasisRollingMaturityAbstract_219635e7-5059-4f82-a032-c8b076d1e744" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis_62d2f607-d45e-44df-89f7-23a91e31f022" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis_8baf2f2c-b341-408f-a9a0-fcc1ec0eb12f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostBasisRollingMaturityAbstract_219635e7-5059-4f82-a032-c8b076d1e744" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis_8baf2f2c-b341-408f-a9a0-fcc1ec0eb12f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis_5c3b79ea-e7b4-4c97-b654-ba018ddfbe5f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostBasisRollingMaturityAbstract_219635e7-5059-4f82-a032-c8b076d1e744" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis_5c3b79ea-e7b4-4c97-b654-ba018ddfbe5f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_63e68a1e-6be7-48e7-8dc1-8f53738e5035" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostBasisRollingMaturityAbstract_219635e7-5059-4f82-a032-c8b076d1e744" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_63e68a1e-6be7-48e7-8dc1-8f53738e5035" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueRollingMaturityAbstract_7016e3cd-63c0-4530-9356-976892e1255e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueRollingMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_86a4684e-79e3-4b6d-a923-d445ee58adce" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueRollingMaturityAbstract_7016e3cd-63c0-4530-9356-976892e1255e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue_ed4cee33-f0d1-48ef-959c-ff09874e8626" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueRollingMaturityAbstract_7016e3cd-63c0-4530-9356-976892e1255e" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue_ed4cee33-f0d1-48ef-959c-ff09874e8626" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue_6a61f2d5-48d8-4e95-ac6a-3e868442521d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueRollingMaturityAbstract_7016e3cd-63c0-4530-9356-976892e1255e" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue_6a61f2d5-48d8-4e95-ac6a-3e868442521d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue_8a2364dd-1da0-498a-a8d7-c64d681b4975" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueRollingMaturityAbstract_7016e3cd-63c0-4530-9356-976892e1255e" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue_8a2364dd-1da0-498a-a8d7-c64d681b4975" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue_8a1cb8fc-4aae-467a-ba11-e374307109e6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueRollingMaturityAbstract_7016e3cd-63c0-4530-9356-976892e1255e" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue_8a1cb8fc-4aae-467a-ba11-e374307109e6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_19da9563-96a0-4028-87a8-598a6e15d4c3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueRollingMaturityAbstract_7016e3cd-63c0-4530-9356-976892e1255e" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_19da9563-96a0-4028-87a8-598a6e15d4c3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleRollingMaturityWeightedAverageYieldAbstract_2864760e-44ca-4d3f-b3f2-d55ee696d5ba" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleRollingMaturityWeightedAverageYieldAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_86a4684e-79e3-4b6d-a923-d445ee58adce" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleRollingMaturityWeightedAverageYieldAbstract_2864760e-44ca-4d3f-b3f2-d55ee696d5ba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleMaturityWithinOneYearWeightedAverageYield_d19405c3-ac67-4560-8505-5110780b54cb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleMaturityWithinOneYearWeightedAverageYield"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleRollingMaturityWeightedAverageYieldAbstract_2864760e-44ca-4d3f-b3f2-d55ee696d5ba" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleMaturityWithinOneYearWeightedAverageYield_d19405c3-ac67-4560-8505-5110780b54cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleMaturityAfterOneThroughFiveYearsWeightedAverageYield_74b78373-2698-491d-9a23-d4823484c5c0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleMaturityAfterOneThroughFiveYearsWeightedAverageYield"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleRollingMaturityWeightedAverageYieldAbstract_2864760e-44ca-4d3f-b3f2-d55ee696d5ba" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleMaturityAfterOneThroughFiveYearsWeightedAverageYield_74b78373-2698-491d-9a23-d4823484c5c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleMaturityAfterFiveThroughTenYearsWeightedAverageYield_7ced0c8e-6042-4696-81fe-aadbcc13cacd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleMaturityAfterFiveThroughTenYearsWeightedAverageYield"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleRollingMaturityWeightedAverageYieldAbstract_2864760e-44ca-4d3f-b3f2-d55ee696d5ba" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleMaturityAfterFiveThroughTenYearsWeightedAverageYield_7ced0c8e-6042-4696-81fe-aadbcc13cacd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleMaturityAfter10YearsWeightedAverageYield_857cf36d-31c1-4580-a2c9-cc5520e34e2a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleMaturityAfter10YearsWeightedAverageYield"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleRollingMaturityWeightedAverageYieldAbstract_2864760e-44ca-4d3f-b3f2-d55ee696d5ba" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleMaturityAfter10YearsWeightedAverageYield_857cf36d-31c1-4580-a2c9-cc5520e34e2a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_DebtSecuritiesAvailableForSaleWeightedAverageYield_384c3ae2-e557-4b5c-a039-c7f2a1b3c5e1" xlink:href="cfb-20200930.xsd#cfb_DebtSecuritiesAvailableForSaleWeightedAverageYield"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleRollingMaturityWeightedAverageYieldAbstract_2864760e-44ca-4d3f-b3f2-d55ee696d5ba" xlink:to="loc_cfb_DebtSecuritiesAvailableForSaleWeightedAverageYield_384c3ae2-e557-4b5c-a039-c7f2a1b3c5e1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_ebd162cc-a1a7-4a9b-927c-15c813fde184" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_86a4684e-79e3-4b6d-a923-d445ee58adce" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_ebd162cc-a1a7-4a9b-927c-15c813fde184" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_38eb4148-5bb5-4015-a928-2b9961efacda" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_ebd162cc-a1a7-4a9b-927c-15c813fde184" xlink:to="loc_us-gaap_FinancialInstrumentAxis_38eb4148-5bb5-4015-a928-2b9961efacda" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_38eb4148-5bb5-4015-a928-2b9961efacda_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_38eb4148-5bb5-4015-a928-2b9961efacda" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_38eb4148-5bb5-4015-a928-2b9961efacda_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_023e2aed-5774-4e42-8d94-99e582d6c47e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_38eb4148-5bb5-4015-a928-2b9961efacda" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_023e2aed-5774-4e42-8d94-99e582d6c47e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_7b3fab18-24df-4046-9faf-e7e3c86399a9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_023e2aed-5774-4e42-8d94-99e582d6c47e" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_7b3fab18-24df-4046-9faf-e7e3c86399a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_CollateralizedMortgageObligationsGovernmentSponsoredEntitiesMember_cc15117f-918b-4b88-865a-f82ce52a119a" xlink:href="cfb-20200930.xsd#cfb_CollateralizedMortgageObligationsGovernmentSponsoredEntitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_023e2aed-5774-4e42-8d94-99e582d6c47e" xlink:to="loc_cfb_CollateralizedMortgageObligationsGovernmentSponsoredEntitiesMember_cc15117f-918b-4b88-865a-f82ce52a119a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_cb17406c-a0d9-4549-87a4-4f20fc0b0bb7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_023e2aed-5774-4e42-8d94-99e582d6c47e" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_cb17406c-a0d9-4549-87a4-4f20fc0b0bb7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateBondSecuritiesMember_829d638e-6aa6-459f-86c1-80334f7e5f1e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateBondSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_023e2aed-5774-4e42-8d94-99e582d6c47e" xlink:to="loc_us-gaap_CorporateBondSecuritiesMember_829d638e-6aa6-459f-86c1-80334f7e5f1e" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/SecuritiesUnrealizedLossesDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#SecuritiesUnrealizedLossesDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/SecuritiesUnrealizedLossesDetails" xlink:type="extended" id="iaca65035c09b4c8ca27afda506b1b467_SecuritiesUnrealizedLossesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_07bcddb7-c502-4317-b59a-2d4813da43a6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesAbstract_5814313b-34b4-419d-8c8e-f215b014505c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_07bcddb7-c502-4317-b59a-2d4813da43a6" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesAbstract_5814313b-34b4-419d-8c8e-f215b014505c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_AvailableForSaleSecuritiesLessThanTwelveMonthsAbstract_6422476b-e6b2-47b2-bb6a-0ded889fb9d8" xlink:href="cfb-20200930.xsd#cfb_AvailableForSaleSecuritiesLessThanTwelveMonthsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_5814313b-34b4-419d-8c8e-f215b014505c" xlink:to="loc_cfb_AvailableForSaleSecuritiesLessThanTwelveMonthsAbstract_6422476b-e6b2-47b2-bb6a-0ded889fb9d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_10891ce8-0ee8-4fa6-9890-2a5946998894" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cfb_AvailableForSaleSecuritiesLessThanTwelveMonthsAbstract_6422476b-e6b2-47b2-bb6a-0ded889fb9d8" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_10891ce8-0ee8-4fa6-9890-2a5946998894" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_455d1e32-5e0b-42fe-85c5-f2602afa6524" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cfb_AvailableForSaleSecuritiesLessThanTwelveMonthsAbstract_6422476b-e6b2-47b2-bb6a-0ded889fb9d8" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_455d1e32-5e0b-42fe-85c5-f2602afa6524" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions_5e417171-5da3-401f-bfc5-77c60f334e4a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cfb_AvailableForSaleSecuritiesLessThanTwelveMonthsAbstract_6422476b-e6b2-47b2-bb6a-0ded889fb9d8" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions_5e417171-5da3-401f-bfc5-77c60f334e4a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_AvailableForSaleSecuritiesTwelveMonthsOrLongerAbstract_3d171f04-2cd9-4548-9c0f-5f4a21ddb607" xlink:href="cfb-20200930.xsd#cfb_AvailableForSaleSecuritiesTwelveMonthsOrLongerAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_5814313b-34b4-419d-8c8e-f215b014505c" xlink:to="loc_cfb_AvailableForSaleSecuritiesTwelveMonthsOrLongerAbstract_3d171f04-2cd9-4548-9c0f-5f4a21ddb607" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_b13ffaf4-529c-4520-8d2e-d2a640d9498c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cfb_AvailableForSaleSecuritiesTwelveMonthsOrLongerAbstract_3d171f04-2cd9-4548-9c0f-5f4a21ddb607" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_b13ffaf4-529c-4520-8d2e-d2a640d9498c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_c92dab15-727b-4cb8-9d82-e25a638d0fc9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cfb_AvailableForSaleSecuritiesTwelveMonthsOrLongerAbstract_3d171f04-2cd9-4548-9c0f-5f4a21ddb607" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_c92dab15-727b-4cb8-9d82-e25a638d0fc9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions_9b4bbf24-f62f-46d0-94af-68345ad3413a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cfb_AvailableForSaleSecuritiesTwelveMonthsOrLongerAbstract_3d171f04-2cd9-4548-9c0f-5f4a21ddb607" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions_9b4bbf24-f62f-46d0-94af-68345ad3413a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGainLossAbstract_d9c629d7-6787-41fb-b65f-45d28671572e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGainLossAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesAbstract_5814313b-34b4-419d-8c8e-f215b014505c" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGainLossAbstract_d9c629d7-6787-41fb-b65f-45d28671572e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_cacf6d99-84e0-4b02-a8f5-6b2969b8c8eb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGainLossAbstract_d9c629d7-6787-41fb-b65f-45d28671572e" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_cacf6d99-84e0-4b02-a8f5-6b2969b8c8eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_83599c41-5694-4fdb-b2bc-23f5ec781b3c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGainLossAbstract_d9c629d7-6787-41fb-b65f-45d28671572e" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_83599c41-5694-4fdb-b2bc-23f5ec781b3c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions_d6f6c2e6-e353-4301-9983-cb153469155e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGainLossAbstract_d9c629d7-6787-41fb-b65f-45d28671572e" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions_d6f6c2e6-e353-4301-9983-cb153469155e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTable_17bfdda8-a20f-4cbc-b19e-c684bb3501d5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_07bcddb7-c502-4317-b59a-2d4813da43a6" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTable_17bfdda8-a20f-4cbc-b19e-c684bb3501d5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_dc96d9fa-54d0-4050-becc-d629db39e8a5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTable_17bfdda8-a20f-4cbc-b19e-c684bb3501d5" xlink:to="loc_us-gaap_FinancialInstrumentAxis_dc96d9fa-54d0-4050-becc-d629db39e8a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dc96d9fa-54d0-4050-becc-d629db39e8a5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_dc96d9fa-54d0-4050-becc-d629db39e8a5" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_dc96d9fa-54d0-4050-becc-d629db39e8a5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5b2571ea-81a9-4cd1-a2db-8dc431b49dc3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_dc96d9fa-54d0-4050-becc-d629db39e8a5" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5b2571ea-81a9-4cd1-a2db-8dc431b49dc3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_3bceb8a5-7150-440e-a8c1-88feadf1178f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5b2571ea-81a9-4cd1-a2db-8dc431b49dc3" xlink:to="loc_us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_3bceb8a5-7150-440e-a8c1-88feadf1178f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_CollateralizedMortgageObligationsGovernmentSponsoredEntitiesMember_dfd5c740-1fc7-407b-b78c-1ac1fa121327" xlink:href="cfb-20200930.xsd#cfb_CollateralizedMortgageObligationsGovernmentSponsoredEntitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5b2571ea-81a9-4cd1-a2db-8dc431b49dc3" xlink:to="loc_cfb_CollateralizedMortgageObligationsGovernmentSponsoredEntitiesMember_dfd5c740-1fc7-407b-b78c-1ac1fa121327" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_add698db-6a24-49bb-a838-4aff4260609d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5b2571ea-81a9-4cd1-a2db-8dc431b49dc3" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_add698db-6a24-49bb-a838-4aff4260609d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateBondSecuritiesMember_9baab348-7806-4375-9692-c8dd86459ac6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateBondSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5b2571ea-81a9-4cd1-a2db-8dc431b49dc3" xlink:to="loc_us-gaap_CorporateBondSecuritiesMember_9baab348-7806-4375-9692-c8dd86459ac6" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/SecuritiesNarrativeDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#SecuritiesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/SecuritiesNarrativeDetails" xlink:type="extended" id="i62dcb397ef234ee48c318e16c109508f_SecuritiesNarrativeDetails"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLL" xlink:type="simple" xlink:href="cfb-20200930.xsd#LoansandAllowanceforLoanLossesALLL"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLL" xlink:type="extended" id="i5f163ed9c5ac4f8f81b0078f2de2c689_LoansandAllowanceforLoanLossesALLL"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLTables" xlink:type="simple" xlink:href="cfb-20200930.xsd#LoansandAllowanceforLoanLossesALLLTables"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLTables" xlink:type="extended" id="i4c28feff646749af902ffb5c7fc36d88_LoansandAllowanceforLoanLossesALLLTables"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLCategoryofLoansDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#LoansandAllowanceforLoanLossesALLLCategoryofLoansDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLCategoryofLoansDetails" xlink:type="extended" id="iff1ea51da9604ec8b163d16382e12e23_LoansandAllowanceforLoanLossesALLLCategoryofLoansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3d910582-f808-469c-93cd-5a9d39aaf2d5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableGross_deb3b467-3d73-4c92-a3b7-543ed67331cb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesReceivableGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3d910582-f808-469c-93cd-5a9d39aaf2d5" xlink:to="loc_us-gaap_NotesReceivableGross_deb3b467-3d73-4c92-a3b7-543ed67331cb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_db0af94b-6094-43a0-a8b1-59d65b3f7cc3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3d910582-f808-469c-93cd-5a9d39aaf2d5" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_db0af94b-6094-43a0-a8b1-59d65b3f7cc3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableDeferredIncome_4bc7a967-6930-453a-a2e1-b58ec9f9b6b1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableDeferredIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3d910582-f808-469c-93cd-5a9d39aaf2d5" xlink:to="loc_us-gaap_FinancingReceivableDeferredIncome_4bc7a967-6930-453a-a2e1-b58ec9f9b6b1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableNet_d5473001-8748-45e9-b468-f7c787bf9f25" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3d910582-f808-469c-93cd-5a9d39aaf2d5" xlink:to="loc_us-gaap_NotesReceivableNet_d5473001-8748-45e9-b468-f7c787bf9f25" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_9d128bae-5c39-41a1-a83e-a37aa302cfe8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_3d910582-f808-469c-93cd-5a9d39aaf2d5" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_9d128bae-5c39-41a1-a83e-a37aa302cfe8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_a9d54773-2375-485f-8209-75879f30f58e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_9d128bae-5c39-41a1-a83e-a37aa302cfe8" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_a9d54773-2375-485f-8209-75879f30f58e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_a9d54773-2375-485f-8209-75879f30f58e_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_a9d54773-2375-485f-8209-75879f30f58e" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_a9d54773-2375-485f-8209-75879f30f58e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_225ab2d9-5f21-486e-a5af-46921cdfef07" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_a9d54773-2375-485f-8209-75879f30f58e" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_225ab2d9-5f21-486e-a5af-46921cdfef07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_f7495c6a-fc86-4b94-a6a2-f59028ea320a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_225ab2d9-5f21-486e-a5af-46921cdfef07" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_f7495c6a-fc86-4b94-a6a2-f59028ea320a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_EnergyPortfolioSegmentMember_013573c4-0de9-411f-b880-7baac172db5c" xlink:href="cfb-20200930.xsd#cfb_EnergyPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_225ab2d9-5f21-486e-a5af-46921cdfef07" xlink:to="loc_cfb_EnergyPortfolioSegmentMember_013573c4-0de9-411f-b880-7baac172db5c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_11e5f782-f162-4504-8602-9d1c60b0bd61" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_225ab2d9-5f21-486e-a5af-46921cdfef07" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_11e5f782-f162-4504-8602-9d1c60b0bd61" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_1e4cc4dd-0637-45f9-9fed-886a7a02187f" xlink:href="cfb-20200930.xsd#cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_225ab2d9-5f21-486e-a5af-46921cdfef07" xlink:to="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_1e4cc4dd-0637-45f9-9fed-886a7a02187f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_605682a3-9e3e-47fd-9ed2-63436d56670d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_225ab2d9-5f21-486e-a5af-46921cdfef07" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_605682a3-9e3e-47fd-9ed2-63436d56670d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_PaymentProtectionProgramMember_bebda8bc-6ca4-4a3a-8574-ca2a0e9f3d25" xlink:href="cfb-20200930.xsd#cfb_PaymentProtectionProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_225ab2d9-5f21-486e-a5af-46921cdfef07" xlink:to="loc_cfb_PaymentProtectionProgramMember_bebda8bc-6ca4-4a3a-8574-ca2a0e9f3d25" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_0e4d377c-c2cb-4eba-90d8-d61383d1e37b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_225ab2d9-5f21-486e-a5af-46921cdfef07" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_0e4d377c-c2cb-4eba-90d8-d61383d1e37b" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLAllowanceforLoanLossesDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#LoansandAllowanceforLoanLossesALLLAllowanceforLoanLossesDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLAllowanceforLoanLossesDetails" xlink:type="extended" id="i6202c1eca05b4df89679588ef0559c4e_LoansandAllowanceforLoanLossesALLLAllowanceforLoanLossesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_59fe9808-da56-4deb-bed8-f9750b4c816b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_b81e378d-42e0-4cc8-861e-bcbc3f8f8f86" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_59fe9808-da56-4deb-bed8-f9750b4c816b" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_b81e378d-42e0-4cc8-861e-bcbc3f8f8f86" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_633b96f1-d3cc-4263-aef7-30dab5071be4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_b81e378d-42e0-4cc8-861e-bcbc3f8f8f86" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_633b96f1-d3cc-4263-aef7-30dab5071be4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForLoanLossesExpensed_27fefe14-9a82-489b-8770-bad437db7fad" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProvisionForLoanLossesExpensed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_b81e378d-42e0-4cc8-861e-bcbc3f8f8f86" xlink:to="loc_us-gaap_ProvisionForLoanLossesExpensed_27fefe14-9a82-489b-8770-bad437db7fad" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_7de24201-8bef-4f0e-a9f2-cf258eac6327" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_b81e378d-42e0-4cc8-861e-bcbc3f8f8f86" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs_7de24201-8bef-4f0e-a9f2-cf258eac6327" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery_66169b36-fa76-4dc8-abfb-4677eb0dc962" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward_b81e378d-42e0-4cc8-861e-bcbc3f8f8f86" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery_66169b36-fa76-4dc8-abfb-4677eb0dc962" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_29beb0ca-711f-4d16-aa9a-fa9205f7e812" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossAdditionalInformationAbstract_556bae7b-2590-4aa1-9be0-975042d8906c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossAdditionalInformationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_59fe9808-da56-4deb-bed8-f9750b4c816b" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossAdditionalInformationAbstract_556bae7b-2590-4aa1-9be0-975042d8906c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1_32e4e02f-4072-4946-a528-3c590c4a12b6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossAdditionalInformationAbstract_556bae7b-2590-4aa1-9be0-975042d8906c" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1_32e4e02f-4072-4946-a528-3c590c4a12b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment_78898ed7-c09e-4e76-b071-180bb44b70aa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossAdditionalInformationAbstract_556bae7b-2590-4aa1-9be0-975042d8906c" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment_78898ed7-c09e-4e76-b071-180bb44b70aa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_fa4ed609-baaf-459e-8db0-bf6ef85d24c3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_FinancingReceivableAdditionalInformationAbstract_d6464e98-32e8-4315-8bbf-032452334019" xlink:href="cfb-20200930.xsd#cfb_FinancingReceivableAdditionalInformationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_59fe9808-da56-4deb-bed8-f9750b4c816b" xlink:to="loc_cfb_FinancingReceivableAdditionalInformationAbstract_d6464e98-32e8-4315-8bbf-032452334019" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment_3f8d3936-36f4-414c-bb04-31ef61a98c9f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cfb_FinancingReceivableAdditionalInformationAbstract_d6464e98-32e8-4315-8bbf-032452334019" xlink:to="loc_us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment_3f8d3936-36f4-414c-bb04-31ef61a98c9f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment_502d06a3-54cd-471f-95cc-4f6266bb0b8c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cfb_FinancingReceivableAdditionalInformationAbstract_d6464e98-32e8-4315-8bbf-032452334019" xlink:to="loc_us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment_502d06a3-54cd-471f-95cc-4f6266bb0b8c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableGross_bac8f0cb-1ac5-4371-a010-bb0870d76fb5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesReceivableGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cfb_FinancingReceivableAdditionalInformationAbstract_d6464e98-32e8-4315-8bbf-032452334019" xlink:to="loc_us-gaap_NotesReceivableGross_bac8f0cb-1ac5-4371-a010-bb0870d76fb5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_7a6a275a-470b-4bf8-bf98-9cd0a5c1d899" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_59fe9808-da56-4deb-bed8-f9750b4c816b" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_7a6a275a-470b-4bf8-bf98-9cd0a5c1d899" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_80eca8f2-ad88-47e2-bcee-47ad3234b505" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_7a6a275a-470b-4bf8-bf98-9cd0a5c1d899" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_80eca8f2-ad88-47e2-bcee-47ad3234b505" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_80eca8f2-ad88-47e2-bcee-47ad3234b505_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_80eca8f2-ad88-47e2-bcee-47ad3234b505" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_80eca8f2-ad88-47e2-bcee-47ad3234b505_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2b5b98b0-2f67-460b-86b8-03f3daef9474" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_80eca8f2-ad88-47e2-bcee-47ad3234b505" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2b5b98b0-2f67-460b-86b8-03f3daef9474" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_83f6d915-49b7-431d-b022-2604d3a3df1e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2b5b98b0-2f67-460b-86b8-03f3daef9474" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_83f6d915-49b7-431d-b022-2604d3a3df1e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_EnergyPortfolioSegmentMember_7e621a07-e239-4dc8-bc4c-4f7c84afdb19" xlink:href="cfb-20200930.xsd#cfb_EnergyPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2b5b98b0-2f67-460b-86b8-03f3daef9474" xlink:to="loc_cfb_EnergyPortfolioSegmentMember_7e621a07-e239-4dc8-bc4c-4f7c84afdb19" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_afc507a7-cd77-4c54-a9ac-dbb490ddd286" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2b5b98b0-2f67-460b-86b8-03f3daef9474" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_afc507a7-cd77-4c54-a9ac-dbb490ddd286" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_85c1682c-8817-4549-b5a2-2f83c7cd6320" xlink:href="cfb-20200930.xsd#cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2b5b98b0-2f67-460b-86b8-03f3daef9474" xlink:to="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_85c1682c-8817-4549-b5a2-2f83c7cd6320" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_9f2f6fe9-89f7-4abf-9ff2-139259543110" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2b5b98b0-2f67-460b-86b8-03f3daef9474" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_9f2f6fe9-89f7-4abf-9ff2-139259543110" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_PaymentProtectionProgramMember_5c1b6555-836e-4f20-8f8a-913d47a71f67" xlink:href="cfb-20200930.xsd#cfb_PaymentProtectionProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2b5b98b0-2f67-460b-86b8-03f3daef9474" xlink:to="loc_cfb_PaymentProtectionProgramMember_5c1b6555-836e-4f20-8f8a-913d47a71f67" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_5b5d8023-f525-456a-b7a4-ea88c73e5397" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_2b5b98b0-2f67-460b-86b8-03f3daef9474" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_5b5d8023-f525-456a-b7a4-ea88c73e5397" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLInternalRiskRatingsDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#LoansandAllowanceforLoanLossesALLLInternalRiskRatingsDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLInternalRiskRatingsDetails" xlink:type="extended" id="ia82b735bc0a54bbda2ea159b02582a5b_LoansandAllowanceforLoanLossesALLLInternalRiskRatingsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_1b5dd443-4bbb-43b1-a3dc-bf926b5819e2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableGross_a6e5e0ad-81c4-4cc4-99be-8d2ae453e0be" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesReceivableGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_1b5dd443-4bbb-43b1-a3dc-bf926b5819e2" xlink:to="loc_us-gaap_NotesReceivableGross_a6e5e0ad-81c4-4cc4-99be-8d2ae453e0be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_3430c876-de81-4596-94b8-820078b623b6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentLineItems_1b5dd443-4bbb-43b1-a3dc-bf926b5819e2" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_3430c876-de81-4596-94b8-820078b623b6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_04ce254a-daac-4749-b336-820cd80968c5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_3430c876-de81-4596-94b8-820078b623b6" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_04ce254a-daac-4749-b336-820cd80968c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_04ce254a-daac-4749-b336-820cd80968c5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_04ce254a-daac-4749-b336-820cd80968c5" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_04ce254a-daac-4749-b336-820cd80968c5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c541c198-73d2-488b-b280-8a3d64928417" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_04ce254a-daac-4749-b336-820cd80968c5" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c541c198-73d2-488b-b280-8a3d64928417" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_df74e2ac-e023-4b57-9a09-1945ec13c0f5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c541c198-73d2-488b-b280-8a3d64928417" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_df74e2ac-e023-4b57-9a09-1945ec13c0f5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_EnergyPortfolioSegmentMember_fbf44d37-a255-4838-abc6-2e38dc40f66d" xlink:href="cfb-20200930.xsd#cfb_EnergyPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c541c198-73d2-488b-b280-8a3d64928417" xlink:to="loc_cfb_EnergyPortfolioSegmentMember_fbf44d37-a255-4838-abc6-2e38dc40f66d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_d82fb9c6-a420-4183-ad40-dbae72e24450" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c541c198-73d2-488b-b280-8a3d64928417" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_d82fb9c6-a420-4183-ad40-dbae72e24450" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_fde5b6ae-b8f8-41c8-afe2-1b0e2bacfa64" xlink:href="cfb-20200930.xsd#cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c541c198-73d2-488b-b280-8a3d64928417" xlink:to="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_fde5b6ae-b8f8-41c8-afe2-1b0e2bacfa64" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_894017b3-8342-43a0-9190-49c5c43d87c2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c541c198-73d2-488b-b280-8a3d64928417" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_894017b3-8342-43a0-9190-49c5c43d87c2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_PaymentProtectionProgramMember_89a9b1ab-8216-4c9d-9d27-2991876c9bc4" xlink:href="cfb-20200930.xsd#cfb_PaymentProtectionProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c541c198-73d2-488b-b280-8a3d64928417" xlink:to="loc_cfb_PaymentProtectionProgramMember_89a9b1ab-8216-4c9d-9d27-2991876c9bc4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_76f79494-c426-4952-babf-354a2c6065f6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_c541c198-73d2-488b-b280-8a3d64928417" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_76f79494-c426-4952-babf-354a2c6065f6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentAxis_d0c9ee5d-92d4-4333-9ff7-b6a0b5b55cf2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InternalCreditAssessmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_3430c876-de81-4596-94b8-820078b623b6" xlink:to="loc_us-gaap_InternalCreditAssessmentAxis_d0c9ee5d-92d4-4333-9ff7-b6a0b5b55cf2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_d0c9ee5d-92d4-4333-9ff7-b6a0b5b55cf2_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_d0c9ee5d-92d4-4333-9ff7-b6a0b5b55cf2" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_d0c9ee5d-92d4-4333-9ff7-b6a0b5b55cf2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalCreditAssessmentDomain_3316a08b-ceba-4cae-95e4-f24cedaabba8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InternalCreditAssessmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InternalCreditAssessmentAxis_d0c9ee5d-92d4-4333-9ff7-b6a0b5b55cf2" xlink:to="loc_us-gaap_InternalCreditAssessmentDomain_3316a08b-ceba-4cae-95e4-f24cedaabba8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PassMember_cefcab05-e943-41a7-b349-5e0a358059a6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PassMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_3316a08b-ceba-4cae-95e4-f24cedaabba8" xlink:to="loc_us-gaap_PassMember_cefcab05-e943-41a7-b349-5e0a358059a6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SpecialMentionMember_36883628-324d-44db-8c1b-4ec6dd12b67f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SpecialMentionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_3316a08b-ceba-4cae-95e4-f24cedaabba8" xlink:to="loc_us-gaap_SpecialMentionMember_36883628-324d-44db-8c1b-4ec6dd12b67f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubstandardMember_b16e59fc-655d-4d8f-989a-6481fd197604" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubstandardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_3316a08b-ceba-4cae-95e4-f24cedaabba8" xlink:to="loc_us-gaap_SubstandardMember_b16e59fc-655d-4d8f-989a-6481fd197604" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DoubtfulMember_bfcc8ec9-802d-4c16-b3ff-a48b1a5773b4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DoubtfulMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_3316a08b-ceba-4cae-95e4-f24cedaabba8" xlink:to="loc_us-gaap_DoubtfulMember_bfcc8ec9-802d-4c16-b3ff-a48b1a5773b4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnlikelyToBeCollectedFinancingReceivableMember_39637ac4-e9ba-4223-b8e2-5363393a56c7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnlikelyToBeCollectedFinancingReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InternalCreditAssessmentDomain_3316a08b-ceba-4cae-95e4-f24cedaabba8" xlink:to="loc_us-gaap_UnlikelyToBeCollectedFinancingReceivableMember_39637ac4-e9ba-4223-b8e2-5363393a56c7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_8ee6b1ed-fc75-4d8a-9b1d-9510ffb87369" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_3430c876-de81-4596-94b8-820078b623b6" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_8ee6b1ed-fc75-4d8a-9b1d-9510ffb87369" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_8ee6b1ed-fc75-4d8a-9b1d-9510ffb87369_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_8ee6b1ed-fc75-4d8a-9b1d-9510ffb87369" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_8ee6b1ed-fc75-4d8a-9b1d-9510ffb87369_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_ca202612-4faf-4a8a-b7ed-357be054803e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentPerformanceStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusAxis_8ee6b1ed-fc75-4d8a-9b1d-9510ffb87369" xlink:to="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_ca202612-4faf-4a8a-b7ed-357be054803e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformingFinancingReceivableMember_6a68d763-b5b9-45e7-b5d9-a5db0d556fb2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PerformingFinancingReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_ca202612-4faf-4a8a-b7ed-357be054803e" xlink:to="loc_us-gaap_PerformingFinancingReceivableMember_6a68d763-b5b9-45e7-b5d9-a5db0d556fb2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonperformingFinancingReceivableMember_81386261-5b05-4f0b-bd34-2733a4148e8e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NonperformingFinancingReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentPerformanceStatusDomain_ca202612-4faf-4a8a-b7ed-357be054803e" xlink:to="loc_us-gaap_NonperformingFinancingReceivableMember_81386261-5b05-4f0b-bd34-2733a4148e8e" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLLoanAgingAnalysisDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#LoansandAllowanceforLoanLossesALLLLoanAgingAnalysisDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLLoanAgingAnalysisDetails" xlink:type="extended" id="i55ac7fc16fec47b59f52ffff4423a603_LoansandAllowanceforLoanLossesALLLLoanAgingAnalysisDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_8f933c1c-a288-4e27-b319-b3e4b46b20b5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDue_02bfd042-0c72-485a-947b-a212afd4f7ce" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_8f933c1c-a288-4e27-b319-b3e4b46b20b5" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDue_02bfd042-0c72-485a-947b-a212afd4f7ce" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentCurrent_e3dd6573-8ca7-4057-b612-8cdb0093c61a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_8f933c1c-a288-4e27-b319-b3e4b46b20b5" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentCurrent_e3dd6573-8ca7-4057-b612-8cdb0093c61a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableGross_41775b7a-15f4-45bc-a378-8d84cdd9e3f1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesReceivableGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_8f933c1c-a288-4e27-b319-b3e4b46b20b5" xlink:to="loc_us-gaap_NotesReceivableGross_41775b7a-15f4-45bc-a378-8d84cdd9e3f1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_32c024fb-b422-4f3c-9609-50be629acd36" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_8f933c1c-a288-4e27-b319-b3e4b46b20b5" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_32c024fb-b422-4f3c-9609-50be629acd36" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_d28a5e00-4b4c-4695-9b23-1bffa9cef991" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfFinancingReceivablesPastDueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_8f933c1c-a288-4e27-b319-b3e4b46b20b5" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_d28a5e00-4b4c-4695-9b23-1bffa9cef991" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_fd1feb08-e7b2-45d3-b411-7645267bf291" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_d28a5e00-4b4c-4695-9b23-1bffa9cef991" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_fd1feb08-e7b2-45d3-b411-7645267bf291" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_fd1feb08-e7b2-45d3-b411-7645267bf291_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_fd1feb08-e7b2-45d3-b411-7645267bf291" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_fd1feb08-e7b2-45d3-b411-7645267bf291_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_db9ef937-5f67-4d66-83e6-792e266a9738" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_fd1feb08-e7b2-45d3-b411-7645267bf291" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_db9ef937-5f67-4d66-83e6-792e266a9738" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_a5ade207-7621-4360-8e0c-ab7a088ad052" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_db9ef937-5f67-4d66-83e6-792e266a9738" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_a5ade207-7621-4360-8e0c-ab7a088ad052" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_EnergyPortfolioSegmentMember_bd5160c0-dcb3-4bcc-8341-822c5099ec14" xlink:href="cfb-20200930.xsd#cfb_EnergyPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_db9ef937-5f67-4d66-83e6-792e266a9738" xlink:to="loc_cfb_EnergyPortfolioSegmentMember_bd5160c0-dcb3-4bcc-8341-822c5099ec14" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_da960930-8526-4f80-b256-ce203965e7c6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_db9ef937-5f67-4d66-83e6-792e266a9738" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_da960930-8526-4f80-b256-ce203965e7c6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_20aeb830-0cd2-4f80-bdc2-5e0b503d8ff3" xlink:href="cfb-20200930.xsd#cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_db9ef937-5f67-4d66-83e6-792e266a9738" xlink:to="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_20aeb830-0cd2-4f80-bdc2-5e0b503d8ff3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_fa091084-2a24-409f-b1a6-67149e565a6b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_db9ef937-5f67-4d66-83e6-792e266a9738" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_fa091084-2a24-409f-b1a6-67149e565a6b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_PaymentProtectionProgramMember_ae8bb871-40a7-4251-ab81-ba26671cab22" xlink:href="cfb-20200930.xsd#cfb_PaymentProtectionProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_db9ef937-5f67-4d66-83e6-792e266a9738" xlink:to="loc_cfb_PaymentProtectionProgramMember_ae8bb871-40a7-4251-ab81-ba26671cab22" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_2696d24f-a0cc-45da-ab94-d36e275ea7e4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_db9ef937-5f67-4d66-83e6-792e266a9738" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_2696d24f-a0cc-45da-ab94-d36e275ea7e4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_ebe324af-b2f4-46a3-8321-2ca1ac7520c4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivablesPastDueTable_d28a5e00-4b4c-4695-9b23-1bffa9cef991" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_ebe324af-b2f4-46a3-8321-2ca1ac7520c4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_ebe324af-b2f4-46a3-8321-2ca1ac7520c4_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_ebe324af-b2f4-46a3-8321-2ca1ac7520c4" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_ebe324af-b2f4-46a3-8321-2ca1ac7520c4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_f2330f08-5bb6-46bc-95ad-623189d97244" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueAxis_ebe324af-b2f4-46a3-8321-2ca1ac7520c4" xlink:to="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_f2330f08-5bb6-46bc-95ad-623189d97244" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_fb7bde50-9ee1-49f4-86d9-9c3cc387b0b6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivables30To59DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_f2330f08-5bb6-46bc-95ad-623189d97244" xlink:to="loc_us-gaap_FinancingReceivables30To59DaysPastDueMember_fb7bde50-9ee1-49f4-86d9-9c3cc387b0b6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_60b3f896-6ac4-4d41-98bf-297fa004e082" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivables60To89DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_f2330f08-5bb6-46bc-95ad-623189d97244" xlink:to="loc_us-gaap_FinancingReceivables60To89DaysPastDueMember_60b3f896-6ac4-4d41-98bf-297fa004e082" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_94acab79-ef7c-4900-82e5-27ba00120861" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablesPeriodPastDueDomain_f2330f08-5bb6-46bc-95ad-623189d97244" xlink:to="loc_us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_94acab79-ef7c-4900-82e5-27ba00120861" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLImpairedLoansDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#LoansandAllowanceforLoanLossesALLLImpairedLoansDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLImpairedLoansDetails" xlink:type="extended" id="idc607356ee5a4ce186b01d6b215fe6ed_LoansandAllowanceforLoanLossesALLLImpairedLoansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableImpairedLineItems_ea45be5b-ee43-413d-9a8d-3cbd7a26e274" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableImpairedLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract_8fbc7d29-ab9c-4c81-85d7-425462451f87" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_ea45be5b-ee43-413d-9a8d-3cbd7a26e274" xlink:to="loc_us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract_8fbc7d29-ab9c-4c81-85d7-425462451f87" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment_f2592ef0-4a84-42a6-91f7-9ba32a17f546" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract_8fbc7d29-ab9c-4c81-85d7-425462451f87" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment_f2592ef0-4a84-42a6-91f7-9ba32a17f546" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment_3ab4151b-98b0-44cf-b245-fb71155a8a1b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract_8fbc7d29-ab9c-4c81-85d7-425462451f87" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment_3ab4151b-98b0-44cf-b245-fb71155a8a1b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableRecordedInvestment_f28c166d-de18-4266-86a7-96e17199f11a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairedFinancingReceivableRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract_8fbc7d29-ab9c-4c81-85d7-425462451f87" xlink:to="loc_us-gaap_ImpairedFinancingReceivableRecordedInvestment_f28c166d-de18-4266-86a7-96e17199f11a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalanceAbstract_653437c7-923c-4104-bd5b-0ad948756842" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalanceAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_ea45be5b-ee43-413d-9a8d-3cbd7a26e274" xlink:to="loc_us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalanceAbstract_653437c7-923c-4104-bd5b-0ad948756842" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance_530069ac-4254-4cac-8104-2a055bc8d817" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalanceAbstract_653437c7-923c-4104-bd5b-0ad948756842" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance_530069ac-4254-4cac-8104-2a055bc8d817" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance_3724e6a0-9e8f-45f2-ae66-42b537b976c6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalanceAbstract_653437c7-923c-4104-bd5b-0ad948756842" xlink:to="loc_us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance_3724e6a0-9e8f-45f2-ae66-42b537b976c6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance_f099bb14-d3a6-4299-892c-8d0b3f67a921" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalanceAbstract_653437c7-923c-4104-bd5b-0ad948756842" xlink:to="loc_us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance_f099bb14-d3a6-4299-892c-8d0b3f67a921" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableRelatedAllowance_7b77755b-5c3e-408d-89f9-376a68d64226" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairedFinancingReceivableRelatedAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_ea45be5b-ee43-413d-9a8d-3cbd7a26e274" xlink:to="loc_us-gaap_ImpairedFinancingReceivableRelatedAllowance_7b77755b-5c3e-408d-89f9-376a68d64226" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_ac5d6648-4c70-4891-8951-19ab32c2918d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfImpairedFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_ea45be5b-ee43-413d-9a8d-3cbd7a26e274" xlink:to="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_ac5d6648-4c70-4891-8951-19ab32c2918d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_04bf56d9-8014-429c-9706-5e4d12f1bebe" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_ac5d6648-4c70-4891-8951-19ab32c2918d" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_04bf56d9-8014-429c-9706-5e4d12f1bebe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_04bf56d9-8014-429c-9706-5e4d12f1bebe_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_04bf56d9-8014-429c-9706-5e4d12f1bebe" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_04bf56d9-8014-429c-9706-5e4d12f1bebe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4381d5a1-c325-4718-a7b4-3157ec0b391b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_04bf56d9-8014-429c-9706-5e4d12f1bebe" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4381d5a1-c325-4718-a7b4-3157ec0b391b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_aefc1fcd-0f46-4fdb-9923-826f4810319f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4381d5a1-c325-4718-a7b4-3157ec0b391b" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_aefc1fcd-0f46-4fdb-9923-826f4810319f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_EnergyPortfolioSegmentMember_999ab8a1-5d49-4fa7-a609-3efb896794cc" xlink:href="cfb-20200930.xsd#cfb_EnergyPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4381d5a1-c325-4718-a7b4-3157ec0b391b" xlink:to="loc_cfb_EnergyPortfolioSegmentMember_999ab8a1-5d49-4fa7-a609-3efb896794cc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_a63a209a-2bc7-4ae5-b257-7e286c781fa4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4381d5a1-c325-4718-a7b4-3157ec0b391b" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_a63a209a-2bc7-4ae5-b257-7e286c781fa4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_a0094723-5c07-4c60-9586-dda0605fad7c" xlink:href="cfb-20200930.xsd#cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4381d5a1-c325-4718-a7b4-3157ec0b391b" xlink:to="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_a0094723-5c07-4c60-9586-dda0605fad7c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_bd8562bc-c52d-4424-b4d5-368c66df0302" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4381d5a1-c325-4718-a7b4-3157ec0b391b" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_bd8562bc-c52d-4424-b4d5-368c66df0302" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_PaymentProtectionProgramMember_7c35a17a-aaab-41ce-bdef-77cf5dff4cbd" xlink:href="cfb-20200930.xsd#cfb_PaymentProtectionProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4381d5a1-c325-4718-a7b4-3157ec0b391b" xlink:to="loc_cfb_PaymentProtectionProgramMember_7c35a17a-aaab-41ce-bdef-77cf5dff4cbd" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_63b8d930-1411-4665-9045-2a68da65baab" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4381d5a1-c325-4718-a7b4-3157ec0b391b" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_63b8d930-1411-4665-9045-2a68da65baab" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLImpairedLoanInterestIncomeandAverageImpairedLoansDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#LoansandAllowanceforLoanLossesALLLImpairedLoanInterestIncomeandAverageImpairedLoansDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLImpairedLoanInterestIncomeandAverageImpairedLoansDetails" xlink:type="extended" id="ifd1a1ffd59264442a794c5b778e6b9e0_LoansandAllowanceforLoanLossesALLLImpairedLoanInterestIncomeandAverageImpairedLoansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableImpairedLineItems_ff8af282-c99e-430d-a311-6fa7c241ed14" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableImpairedLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod_633181e3-3267-42a1-938a-27399c6f0d4c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_ff8af282-c99e-430d-a311-6fa7c241ed14" xlink:to="loc_us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod_633181e3-3267-42a1-938a-27399c6f0d4c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment_1fda25a0-834c-4266-ac3e-9ccea34669ac" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_ff8af282-c99e-430d-a311-6fa7c241ed14" xlink:to="loc_us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment_1fda25a0-834c-4266-ac3e-9ccea34669ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_e7d373ad-66b7-4916-81fd-d1088d81dd55" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfImpairedFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableImpairedLineItems_ff8af282-c99e-430d-a311-6fa7c241ed14" xlink:to="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_e7d373ad-66b7-4916-81fd-d1088d81dd55" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_3e994636-8465-486f-b867-432bb652ae44" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfImpairedFinancingReceivableTable_e7d373ad-66b7-4916-81fd-d1088d81dd55" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_3e994636-8465-486f-b867-432bb652ae44" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_3e994636-8465-486f-b867-432bb652ae44_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_3e994636-8465-486f-b867-432bb652ae44" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_3e994636-8465-486f-b867-432bb652ae44_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4b4a0492-020e-4cce-aa0d-f6471a670681" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_3e994636-8465-486f-b867-432bb652ae44" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4b4a0492-020e-4cce-aa0d-f6471a670681" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_40ee8531-ca49-4696-8aa4-5399f6d7dba4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4b4a0492-020e-4cce-aa0d-f6471a670681" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_40ee8531-ca49-4696-8aa4-5399f6d7dba4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_EnergyPortfolioSegmentMember_ffde4800-92b1-4335-ace6-cf66c6d07518" xlink:href="cfb-20200930.xsd#cfb_EnergyPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4b4a0492-020e-4cce-aa0d-f6471a670681" xlink:to="loc_cfb_EnergyPortfolioSegmentMember_ffde4800-92b1-4335-ace6-cf66c6d07518" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_703a973e-a30b-425b-a8f4-10b50bd0b683" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4b4a0492-020e-4cce-aa0d-f6471a670681" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_703a973e-a30b-425b-a8f4-10b50bd0b683" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_1e052eeb-2a2d-47f5-9497-8b7ccbe4ec20" xlink:href="cfb-20200930.xsd#cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4b4a0492-020e-4cce-aa0d-f6471a670681" xlink:to="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_1e052eeb-2a2d-47f5-9497-8b7ccbe4ec20" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_7ae23566-6ed6-421f-9a9d-5bbecb9d663b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4b4a0492-020e-4cce-aa0d-f6471a670681" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_7ae23566-6ed6-421f-9a9d-5bbecb9d663b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_PaymentProtectionProgramMember_0c777a1b-7641-4595-801d-52e30c70d247" xlink:href="cfb-20200930.xsd#cfb_PaymentProtectionProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4b4a0492-020e-4cce-aa0d-f6471a670681" xlink:to="loc_cfb_PaymentProtectionProgramMember_0c777a1b-7641-4595-801d-52e30c70d247" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_22d6c3c8-6d65-47e4-81e9-ba0d8ba04d83" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_4b4a0492-020e-4cce-aa0d-f6471a670681" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_22d6c3c8-6d65-47e4-81e9-ba0d8ba04d83" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLNonAccrualLoansDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#LoansandAllowanceforLoanLossesALLLNonAccrualLoansDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLNonAccrualLoansDetails" xlink:type="extended" id="i0b113d9c3cee440eb0e614ea38c95bff_LoansandAllowanceforLoanLossesALLLNonAccrualLoansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableNonaccrualStatusLineItems_2e48c07e-3ecb-475b-b6cf-f7284ef29d1c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableNonaccrualStatusLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_48ef3e59-f070-4aa2-9728-2f1b54e1b194" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualStatusLineItems_2e48c07e-3ecb-475b-b6cf-f7284ef29d1c" xlink:to="loc_us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_48ef3e59-f070-4aa2-9728-2f1b54e1b194" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableNonaccrualTable_2606a522-e4f6-47e0-8346-a904f02767cf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableNonaccrualTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualStatusLineItems_2e48c07e-3ecb-475b-b6cf-f7284ef29d1c" xlink:to="loc_us-gaap_FinancingReceivableNonaccrualTable_2606a522-e4f6-47e0-8346-a904f02767cf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_f629b5c5-cae2-44bb-b6fd-d9ad9d564bd8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FinancingReceivableNonaccrualTable_2606a522-e4f6-47e0-8346-a904f02767cf" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_f629b5c5-cae2-44bb-b6fd-d9ad9d564bd8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_f629b5c5-cae2-44bb-b6fd-d9ad9d564bd8_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_f629b5c5-cae2-44bb-b6fd-d9ad9d564bd8" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_f629b5c5-cae2-44bb-b6fd-d9ad9d564bd8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_e5610c1b-154b-4cc0-a4d0-2360b94eb462" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_f629b5c5-cae2-44bb-b6fd-d9ad9d564bd8" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_e5610c1b-154b-4cc0-a4d0-2360b94eb462" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_30140d62-0a8b-44fe-b7db-11f783c19782" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_e5610c1b-154b-4cc0-a4d0-2360b94eb462" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_30140d62-0a8b-44fe-b7db-11f783c19782" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_EnergyPortfolioSegmentMember_b77cdef2-28f8-4383-b4e4-2441510b9362" xlink:href="cfb-20200930.xsd#cfb_EnergyPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_e5610c1b-154b-4cc0-a4d0-2360b94eb462" xlink:to="loc_cfb_EnergyPortfolioSegmentMember_b77cdef2-28f8-4383-b4e4-2441510b9362" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_23b7ca03-bf9d-478e-9c84-1556ad6d8dfd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_e5610c1b-154b-4cc0-a4d0-2360b94eb462" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_23b7ca03-bf9d-478e-9c84-1556ad6d8dfd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_f3da4d05-bc72-4663-adb8-42feb173a5db" xlink:href="cfb-20200930.xsd#cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_e5610c1b-154b-4cc0-a4d0-2360b94eb462" xlink:to="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_f3da4d05-bc72-4663-adb8-42feb173a5db" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_98e24465-8d1f-478f-8282-acade7e4ed53" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_e5610c1b-154b-4cc0-a4d0-2360b94eb462" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_98e24465-8d1f-478f-8282-acade7e4ed53" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_PaymentProtectionProgramMember_0eaa4edf-b129-43f0-aadb-588e4daec6df" xlink:href="cfb-20200930.xsd#cfb_PaymentProtectionProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_e5610c1b-154b-4cc0-a4d0-2360b94eb462" xlink:to="loc_cfb_PaymentProtectionProgramMember_0eaa4edf-b129-43f0-aadb-588e4daec6df" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_8232702b-3705-4516-90a1-3cd0f54d11b1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_e5610c1b-154b-4cc0-a4d0-2360b94eb462" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_8232702b-3705-4516-90a1-3cd0f54d11b1" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLTroubledDebtRestructuringLoansDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#LoansandAllowanceforLoanLossesALLLTroubledDebtRestructuringLoansDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/LoansandAllowanceforLoanLossesALLLTroubledDebtRestructuringLoansDetails" xlink:type="extended" id="i3c849b916d0a4d58a0a06f8291fd7827_LoansandAllowanceforLoanLossesALLLTroubledDebtRestructuringLoansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsLineItems_4c797ce2-8ad2-4e40-bfc9-e3f4b63c02f2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableModificationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_e23b8cab-0392-4633-aa77-96a0ddcb6837" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_4c797ce2-8ad2-4e40-bfc9-e3f4b63c02f2" xlink:to="loc_us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_e23b8cab-0392-4633-aa77-96a0ddcb6837" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_561f5c2c-e4a5-482e-828c-19aebdb32fb7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableModificationsNumberOfContracts2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_4c797ce2-8ad2-4e40-bfc9-e3f4b63c02f2" xlink:to="loc_us-gaap_FinancingReceivableModificationsNumberOfContracts2_561f5c2c-e4a5-482e-828c-19aebdb32fb7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsRecordedInvestment_29f6f01e-8ca2-4cbc-b23e-c883db8c6822" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableModificationsRecordedInvestment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_4c797ce2-8ad2-4e40-bfc9-e3f4b63c02f2" xlink:to="loc_us-gaap_FinancingReceivableModificationsRecordedInvestment_29f6f01e-8ca2-4cbc-b23e-c883db8c6822" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1_b93ddf88-4874-41b0-b78a-d83603506c7f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_4c797ce2-8ad2-4e40-bfc9-e3f4b63c02f2" xlink:to="loc_us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1_b93ddf88-4874-41b0-b78a-d83603506c7f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_FinancingReceivableAllowanceForCreditLossIncreaseDecreaseFromModification_d8790ac7-29ca-4f58-9e15-2ba14f6af2e0" xlink:href="cfb-20200930.xsd#cfb_FinancingReceivableAllowanceForCreditLossIncreaseDecreaseFromModification"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_4c797ce2-8ad2-4e40-bfc9-e3f4b63c02f2" xlink:to="loc_cfb_FinancingReceivableAllowanceForCreditLossIncreaseDecreaseFromModification_d8790ac7-29ca-4f58-9e15-2ba14f6af2e0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_c3db7129-344d-4cfa-96f9-882e38b4bd9a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FinancingReceivableModificationsLineItems_4c797ce2-8ad2-4e40-bfc9-e3f4b63c02f2" xlink:to="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_c3db7129-344d-4cfa-96f9-882e38b4bd9a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationAxis_eefca303-1cc9-44fb-8d6f-ece46702eeec" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoanRestructuringModificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_c3db7129-344d-4cfa-96f9-882e38b4bd9a" xlink:to="loc_us-gaap_LoanRestructuringModificationAxis_eefca303-1cc9-44fb-8d6f-ece46702eeec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_eefca303-1cc9-44fb-8d6f-ece46702eeec_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_eefca303-1cc9-44fb-8d6f-ece46702eeec" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_eefca303-1cc9-44fb-8d6f-ece46702eeec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanRestructuringModificationDomain_51548866-1241-4015-8a04-3affe556a05a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoanRestructuringModificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LoanRestructuringModificationAxis_eefca303-1cc9-44fb-8d6f-ece46702eeec" xlink:to="loc_us-gaap_LoanRestructuringModificationDomain_51548866-1241-4015-8a04-3affe556a05a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualInterestRateReductionMember_f882b9e8-849d-49e0-81d4-041e79c0e190" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractualInterestRateReductionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_51548866-1241-4015-8a04-3affe556a05a" xlink:to="loc_us-gaap_ContractualInterestRateReductionMember_f882b9e8-849d-49e0-81d4-041e79c0e190" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ReductionOfMonthlyPaymentMember_6a1978f1-123d-43ea-b252-7c3783883aa3" xlink:href="cfb-20200930.xsd#cfb_ReductionOfMonthlyPaymentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_51548866-1241-4015-8a04-3affe556a05a" xlink:to="loc_cfb_ReductionOfMonthlyPaymentMember_6a1978f1-123d-43ea-b252-7c3783883aa3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtendedMaturityMember_5ca52c9d-96eb-4dea-9dbf-c0c89f83fb2b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ExtendedMaturityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_51548866-1241-4015-8a04-3affe556a05a" xlink:to="loc_us-gaap_ExtendedMaturityMember_5ca52c9d-96eb-4dea-9dbf-c0c89f83fb2b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentDeferralMember_97076d1d-3144-4a4d-b11d-445fd084578b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentDeferralMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanRestructuringModificationDomain_51548866-1241-4015-8a04-3affe556a05a" xlink:to="loc_us-gaap_PaymentDeferralMember_97076d1d-3144-4a4d-b11d-445fd084578b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_cd032bff-6864-4a4c-90b9-558ba21e76c9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_c3db7129-344d-4cfa-96f9-882e38b4bd9a" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_cd032bff-6864-4a4c-90b9-558ba21e76c9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_cd032bff-6864-4a4c-90b9-558ba21e76c9_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_cd032bff-6864-4a4c-90b9-558ba21e76c9" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_cd032bff-6864-4a4c-90b9-558ba21e76c9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f01de30-ca24-407c-bc76-9c9c9fe08607" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancingReceivablePortfolioSegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentAxis_cd032bff-6864-4a4c-90b9-558ba21e76c9" xlink:to="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f01de30-ca24-407c-bc76-9c9c9fe08607" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPortfolioSegmentMember_e1d14b45-868f-4d1c-9f69-5297bac1e009" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f01de30-ca24-407c-bc76-9c9c9fe08607" xlink:to="loc_us-gaap_CommercialPortfolioSegmentMember_e1d14b45-868f-4d1c-9f69-5297bac1e009" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_EnergyPortfolioSegmentMember_b6d027c2-a50d-4e6b-894c-e53cd3c8840e" xlink:href="cfb-20200930.xsd#cfb_EnergyPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f01de30-ca24-407c-bc76-9c9c9fe08607" xlink:to="loc_cfb_EnergyPortfolioSegmentMember_b6d027c2-a50d-4e6b-894c-e53cd3c8840e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_c7247399-b715-475c-a934-8622d9f08b14" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialRealEstatePortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f01de30-ca24-407c-bc76-9c9c9fe08607" xlink:to="loc_us-gaap_CommercialRealEstatePortfolioSegmentMember_c7247399-b715-475c-a934-8622d9f08b14" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_36eca780-a102-4ff8-a9f2-e9114e472339" xlink:href="cfb-20200930.xsd#cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f01de30-ca24-407c-bc76-9c9c9fe08607" xlink:to="loc_cfb_ConstructionAndLandDevelopmentPortfolioSegmentMember_36eca780-a102-4ff8-a9f2-e9114e472339" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialPortfolioSegmentMember_9a4793f2-0c48-4aae-bcc1-39078742bcde" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResidentialPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f01de30-ca24-407c-bc76-9c9c9fe08607" xlink:to="loc_us-gaap_ResidentialPortfolioSegmentMember_9a4793f2-0c48-4aae-bcc1-39078742bcde" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_PaymentProtectionProgramMember_4d78d8f8-c8f6-499b-b09c-b3d450d83d4e" xlink:href="cfb-20200930.xsd#cfb_PaymentProtectionProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f01de30-ca24-407c-bc76-9c9c9fe08607" xlink:to="loc_cfb_PaymentProtectionProgramMember_4d78d8f8-c8f6-499b-b09c-b3d450d83d4e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsumerPortfolioSegmentMember_5504b3d0-4dcf-471f-978e-7c9d7282a007" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConsumerPortfolioSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancingReceivablePortfolioSegmentDomain_5f01de30-ca24-407c-bc76-9c9c9fe08607" xlink:to="loc_us-gaap_ConsumerPortfolioSegmentMember_5504b3d0-4dcf-471f-978e-7c9d7282a007" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/DerivativesandHedging" xlink:type="simple" xlink:href="cfb-20200930.xsd#DerivativesandHedging"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/DerivativesandHedging" xlink:type="extended" id="i2934271cce1b4ddcadfc1e77093019ec_DerivativesandHedging"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/DerivativesandHedgingTables" xlink:type="simple" xlink:href="cfb-20200930.xsd#DerivativesandHedgingTables"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/DerivativesandHedgingTables" xlink:type="extended" id="i12bda430c23b4063b2a47b2c14902d24_DerivativesandHedgingTables"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/DerivativesandHedgingOutstandingDerivativesDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#DerivativesandHedgingOutstandingDerivativesDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/DerivativesandHedgingOutstandingDerivativesDetails" xlink:type="extended" id="if11e0df5650243769c3553a537495fe9_DerivativesandHedgingOutstandingDerivativesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_269e4674-756b-42fc-bfac-f18a303e07b4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNumberOfInstrumentsHeld_8c45250a-2ab9-410e-80d3-dadd4e06519a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeNumberOfInstrumentsHeld"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_269e4674-756b-42fc-bfac-f18a303e07b4" xlink:to="loc_us-gaap_DerivativeNumberOfInstrumentsHeld_8c45250a-2ab9-410e-80d3-dadd4e06519a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_e89228a7-78ae-4292-8feb-c6f72b0165be" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_269e4674-756b-42fc-bfac-f18a303e07b4" xlink:to="loc_us-gaap_DerivativeNotionalAmount_e89228a7-78ae-4292-8feb-c6f72b0165be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_269b764a-b101-4598-8541-1d4f74278c7b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_269e4674-756b-42fc-bfac-f18a303e07b4" xlink:to="loc_us-gaap_DerivativeTable_269b764a-b101-4598-8541-1d4f74278c7b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_3c55bbd7-91ac-426b-bb1d-b827cfc67f48" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_269b764a-b101-4598-8541-1d4f74278c7b" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_3c55bbd7-91ac-426b-bb1d-b827cfc67f48" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_3c55bbd7-91ac-426b-bb1d-b827cfc67f48_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_3c55bbd7-91ac-426b-bb1d-b827cfc67f48" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_3c55bbd7-91ac-426b-bb1d-b827cfc67f48_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_2cf52cf3-48c4-4bae-b1d7-e4037931e9ea" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_3c55bbd7-91ac-426b-bb1d-b827cfc67f48" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_2cf52cf3-48c4-4bae-b1d7-e4037931e9ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_3943b9e7-6952-4424-ab50-826e587f3423" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_2cf52cf3-48c4-4bae-b1d7-e4037931e9ea" xlink:to="loc_us-gaap_InterestRateSwapMember_3943b9e7-6952-4424-ab50-826e587f3423" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_a958f01b-5cc8-4f1d-821d-1d41457da562" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_269b764a-b101-4598-8541-1d4f74278c7b" xlink:to="loc_us-gaap_HedgingDesignationAxis_a958f01b-5cc8-4f1d-821d-1d41457da562" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_a958f01b-5cc8-4f1d-821d-1d41457da562_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_a958f01b-5cc8-4f1d-821d-1d41457da562" xlink:to="loc_us-gaap_HedgingDesignationDomain_a958f01b-5cc8-4f1d-821d-1d41457da562_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_5e3c8979-83d6-4810-bd1d-a2071bae92a5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_a958f01b-5cc8-4f1d-821d-1d41457da562" xlink:to="loc_us-gaap_HedgingDesignationDomain_5e3c8979-83d6-4810-bd1d-a2071bae92a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_ebb0bdf9-5fa1-4b00-90f4-795fa3ac50c5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_5e3c8979-83d6-4810-bd1d-a2071bae92a5" xlink:to="loc_us-gaap_NondesignatedMember_ebb0bdf9-5fa1-4b00-90f4-795fa3ac50c5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/DerivativesandHedgingFairValueofDerivativesDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#DerivativesandHedgingFairValueofDerivativesDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/DerivativesandHedgingFairValueofDerivativesDetails" xlink:type="extended" id="id066988612ed48868cc25dc8f0891a11_DerivativesandHedgingFairValueofDerivativesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_936198b0-5233-46c7-98f9-5cb5c6690b9f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_531240d5-fb9c-499d-994b-649f45349a6a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_936198b0-5233-46c7-98f9-5cb5c6690b9f" xlink:to="loc_us-gaap_DerivativeAssets_531240d5-fb9c-499d-994b-649f45349a6a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_85ff0deb-c77f-417e-8406-1e133a6dbd8a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_936198b0-5233-46c7-98f9-5cb5c6690b9f" xlink:to="loc_us-gaap_DerivativeLiabilities_85ff0deb-c77f-417e-8406-1e133a6dbd8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_1f532ae9-8c13-4779-ae3c-34b52ccd58ed" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_936198b0-5233-46c7-98f9-5cb5c6690b9f" xlink:to="loc_us-gaap_DerivativeTable_1f532ae9-8c13-4779-ae3c-34b52ccd58ed" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_f17f9e73-3c9e-486a-bc3e-c4f2d3c6c169" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_1f532ae9-8c13-4779-ae3c-34b52ccd58ed" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_f17f9e73-3c9e-486a-bc3e-c4f2d3c6c169" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_f17f9e73-3c9e-486a-bc3e-c4f2d3c6c169_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_f17f9e73-3c9e-486a-bc3e-c4f2d3c6c169" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_f17f9e73-3c9e-486a-bc3e-c4f2d3c6c169_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_2b8950b2-4d8b-4eab-8b5a-2ccc6d231ca1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_f17f9e73-3c9e-486a-bc3e-c4f2d3c6c169" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_2b8950b2-4d8b-4eab-8b5a-2ccc6d231ca1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsMember_eeee3242-b89d-4f37-b118-f69bf3fc92ed" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_2b8950b2-4d8b-4eab-8b5a-2ccc6d231ca1" xlink:to="loc_us-gaap_OtherAssetsMember_eeee3242-b89d-4f37-b118-f69bf3fc92ed" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesMember_bb06b717-6a76-4d30-bc04-695bbd1bc0f9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_2b8950b2-4d8b-4eab-8b5a-2ccc6d231ca1" xlink:to="loc_us-gaap_OtherLiabilitiesMember_bb06b717-6a76-4d30-bc04-695bbd1bc0f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_8f155b52-3124-46ec-b727-01e119ecff3b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_1f532ae9-8c13-4779-ae3c-34b52ccd58ed" xlink:to="loc_us-gaap_HedgingDesignationAxis_8f155b52-3124-46ec-b727-01e119ecff3b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_8f155b52-3124-46ec-b727-01e119ecff3b_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_8f155b52-3124-46ec-b727-01e119ecff3b" xlink:to="loc_us-gaap_HedgingDesignationDomain_8f155b52-3124-46ec-b727-01e119ecff3b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_0678b352-f2bd-4660-b5c9-df6a83fb3f0c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_8f155b52-3124-46ec-b727-01e119ecff3b" xlink:to="loc_us-gaap_HedgingDesignationDomain_0678b352-f2bd-4660-b5c9-df6a83fb3f0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_9a4bfb7a-cbf3-40d2-b068-d7f17b4cd417" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_0678b352-f2bd-4660-b5c9-df6a83fb3f0c" xlink:to="loc_us-gaap_NondesignatedMember_9a4bfb7a-cbf3-40d2-b068-d7f17b4cd417" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_7152bb72-8c76-445b-aa92-73471ec50c87" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_1f532ae9-8c13-4779-ae3c-34b52ccd58ed" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_7152bb72-8c76-445b-aa92-73471ec50c87" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_7152bb72-8c76-445b-aa92-73471ec50c87_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_7152bb72-8c76-445b-aa92-73471ec50c87" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_7152bb72-8c76-445b-aa92-73471ec50c87_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_c82f6c24-774c-4e4b-96f5-672e04bfc1ea" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_7152bb72-8c76-445b-aa92-73471ec50c87" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_c82f6c24-774c-4e4b-96f5-672e04bfc1ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateContractMember_58d16dcf-7505-48b3-8967-cc2aedb3097b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c82f6c24-774c-4e4b-96f5-672e04bfc1ea" xlink:to="loc_us-gaap_InterestRateContractMember_58d16dcf-7505-48b3-8967-cc2aedb3097b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/GoodwillandOtherIntangibleAssets" xlink:type="simple" xlink:href="cfb-20200930.xsd#GoodwillandOtherIntangibleAssets"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/GoodwillandOtherIntangibleAssets" xlink:type="extended" id="i88ba2ae024d54d19a60c4761e1fb3ef7_GoodwillandOtherIntangibleAssets"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/GoodwillandOtherIntangibleAssetsTables" xlink:type="simple" xlink:href="cfb-20200930.xsd#GoodwillandOtherIntangibleAssetsTables"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/GoodwillandOtherIntangibleAssetsTables" xlink:type="extended" id="i16f8a1542e5242a48d3c16388923f60c_GoodwillandOtherIntangibleAssetsTables"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/GoodwillandOtherIntangibleAssetsNarrativeDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#GoodwillandOtherIntangibleAssetsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/GoodwillandOtherIntangibleAssetsNarrativeDetails" xlink:type="extended" id="id2dcbd14df274e4bb11582bbee70a500_GoodwillandOtherIntangibleAssetsNarrativeDetails"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/GoodwillandOtherIntangibleAssetsScheduleofIntangibleAssetsandGoodwillDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#GoodwillandOtherIntangibleAssetsScheduleofIntangibleAssetsandGoodwillDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/GoodwillandOtherIntangibleAssetsScheduleofIntangibleAssetsandGoodwillDetails" xlink:type="extended" id="i8b006a156f8745c4a7e561f57c800c18_GoodwillandOtherIntangibleAssetsScheduleofIntangibleAssetsandGoodwillDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_ab063b64-eca6-4f52-8289-444748eb8d70" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_fb87703d-973c-4eec-981b-defbffe6eb0b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_ab063b64-eca6-4f52-8289-444748eb8d70" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_fb87703d-973c-4eec-981b-defbffe6eb0b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_b620ebc9-38aa-4e6b-8d14-8a17ac239076" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_fb87703d-973c-4eec-981b-defbffe6eb0b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_b620ebc9-38aa-4e6b-8d14-8a17ac239076" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_fafbe16b-19dc-45c1-b4aa-2f584021e97e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ImpairmentOfIntangibleAssetsFinitelived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_fb87703d-973c-4eec-981b-defbffe6eb0b" xlink:to="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_fafbe16b-19dc-45c1-b4aa-2f584021e97e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_d1bf46f9-0461-409d-a591-656f58735390" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_fb87703d-973c-4eec-981b-defbffe6eb0b" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_d1bf46f9-0461-409d-a591-656f58735390" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_d5626a20-7153-4c03-b427-ffbbe5c9d295" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a6995fa1-9ff1-4294-ae94-7d8b2d4cc783" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_ab063b64-eca6-4f52-8289-444748eb8d70" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a6995fa1-9ff1-4294-ae94-7d8b2d4cc783" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_60227590-261b-4db0-a72c-1f742a5939bf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a6995fa1-9ff1-4294-ae94-7d8b2d4cc783" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_60227590-261b-4db0-a72c-1f742a5939bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_60227590-261b-4db0-a72c-1f742a5939bf_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_60227590-261b-4db0-a72c-1f742a5939bf" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_60227590-261b-4db0-a72c-1f742a5939bf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_bfa3027a-2739-4dca-89ff-8bab1f0a9861" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_60227590-261b-4db0-a72c-1f742a5939bf" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_bfa3027a-2739-4dca-89ff-8bab1f0a9861" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CoreDepositsMember_b4896231-51ad-4265-8776-056aef2926a5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CoreDepositsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_bfa3027a-2739-4dca-89ff-8bab1f0a9861" xlink:to="loc_us-gaap_CoreDepositsMember_b4896231-51ad-4265-8776-056aef2926a5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/TimeDepositsandBorrowings" xlink:type="simple" xlink:href="cfb-20200930.xsd#TimeDepositsandBorrowings"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/TimeDepositsandBorrowings" xlink:type="extended" id="i7d05623bc9644e00adbf06b1fb5c4133_TimeDepositsandBorrowings"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/TimeDepositsandBorrowingsTables" xlink:type="simple" xlink:href="cfb-20200930.xsd#TimeDepositsandBorrowingsTables"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/TimeDepositsandBorrowingsTables" xlink:type="extended" id="ida6d4fef5d784df89477975b7ee6fc23_TimeDepositsandBorrowingsTables"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/TimeDepositsandBorrowingsDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#TimeDepositsandBorrowingsDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/TimeDepositsandBorrowingsDetails" xlink:type="extended" id="iaf9463599b744120b567c4250b76f461_TimeDepositsandBorrowingsDetails"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/ChangeinAccumulatedOtherComprehensiveIncomeAOCI" xlink:type="simple" xlink:href="cfb-20200930.xsd#ChangeinAccumulatedOtherComprehensiveIncomeAOCI"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/ChangeinAccumulatedOtherComprehensiveIncomeAOCI" xlink:type="extended" id="ie95fe96d9c984cf9aae9769a4cc89a2a_ChangeinAccumulatedOtherComprehensiveIncomeAOCI"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/ChangeinAccumulatedOtherComprehensiveIncomeAOCITables" xlink:type="simple" xlink:href="cfb-20200930.xsd#ChangeinAccumulatedOtherComprehensiveIncomeAOCITables"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/ChangeinAccumulatedOtherComprehensiveIncomeAOCITables" xlink:type="extended" id="i5462db1625b64e5bb62d78e08eab7220_ChangeinAccumulatedOtherComprehensiveIncomeAOCITables"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/ChangeinAccumulatedOtherComprehensiveIncomeAOCIDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#ChangeinAccumulatedOtherComprehensiveIncomeAOCIDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/ChangeinAccumulatedOtherComprehensiveIncomeAOCIDetails" xlink:type="extended" id="i76a78a7bccdd41e1ad7b9e4c9f8c1f39_ChangeinAccumulatedOtherComprehensiveIncomeAOCIDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_31aab3be-a00f-4204-87e6-e7bb86e3f235" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnInvestments_810fb332-af26-4b85-8cf9-71b1d3136086" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GainLossOnInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_31aab3be-a00f-4204-87e6-e7bb86e3f235" xlink:to="loc_us-gaap_GainLossOnInvestments_810fb332-af26-4b85-8cf9-71b1d3136086" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_f940a240-26f8-428b-9b2e-43b6683e5d4f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_31aab3be-a00f-4204-87e6-e7bb86e3f235" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_f940a240-26f8-428b-9b2e-43b6683e5d4f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_f3db25f2-2906-40f5-a153-13784327e149" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_31aab3be-a00f-4204-87e6-e7bb86e3f235" xlink:to="loc_us-gaap_NetIncomeLoss_f3db25f2-2906-40f5-a153-13784327e149" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_996241d4-25f9-44c3-b8c8-9b5431c90dad" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_31aab3be-a00f-4204-87e6-e7bb86e3f235" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_996241d4-25f9-44c3-b8c8-9b5431c90dad" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_cfaca12d-676f-4485-bee8-f6ad59fcdd4d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_996241d4-25f9-44c3-b8c8-9b5431c90dad" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_cfaca12d-676f-4485-bee8-f6ad59fcdd4d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_cfaca12d-676f-4485-bee8-f6ad59fcdd4d_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_cfaca12d-676f-4485-bee8-f6ad59fcdd4d" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_cfaca12d-676f-4485-bee8-f6ad59fcdd4d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_575df438-7915-4a63-8ca7-08018bb9b273" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_cfaca12d-676f-4485-bee8-f6ad59fcdd4d" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_575df438-7915-4a63-8ca7-08018bb9b273" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_d1055899-b88c-43db-b4bd-c590107a9ba5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_575df438-7915-4a63-8ca7-08018bb9b273" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_d1055899-b88c-43db-b4bd-c590107a9ba5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/RegulatoryMatters" xlink:type="simple" xlink:href="cfb-20200930.xsd#RegulatoryMatters"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/RegulatoryMatters" xlink:type="extended" id="i8fd9ac9ef1a541099b477316a5b69903_RegulatoryMatters"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/RegulatoryMattersTables" xlink:type="simple" xlink:href="cfb-20200930.xsd#RegulatoryMattersTables"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/RegulatoryMattersTables" xlink:type="extended" id="id9130a47934b4c1287415d96775d6a97_RegulatoryMattersTables"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/RegulatoryMattersDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#RegulatoryMattersDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/RegulatoryMattersDetails" xlink:type="extended" id="i86834ef7fe4e4c80a82470e931052d32_RegulatoryMattersDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_6da3c701-b584-483d-9b12-97f7676668b3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalAbstract_70a1a708-a0c4-4993-8cf8-738b205c123c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_6da3c701-b584-483d-9b12-97f7676668b3" xlink:to="loc_us-gaap_CapitalAbstract_70a1a708-a0c4-4993-8cf8-738b205c123c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Capital_5e64213f-d72f-49f5-a1a5-05181e297e7e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Capital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalAbstract_70a1a708-a0c4-4993-8cf8-738b205c123c" xlink:to="loc_us-gaap_Capital_5e64213f-d72f-49f5-a1a5-05181e297e7e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalToRiskWeightedAssets_d64c8750-521a-448e-b1a4-eb6aae7b4e5c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalToRiskWeightedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalAbstract_70a1a708-a0c4-4993-8cf8-738b205c123c" xlink:to="loc_us-gaap_CapitalToRiskWeightedAssets_d64c8750-521a-448e-b1a4-eb6aae7b4e5c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalRequiredForCapitalAdequacy_25c451c8-1906-43aa-beee-ba4693e2ba8c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalRequiredForCapitalAdequacy"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalAbstract_70a1a708-a0c4-4993-8cf8-738b205c123c" xlink:to="loc_us-gaap_CapitalRequiredForCapitalAdequacy_25c451c8-1906-43aa-beee-ba4693e2ba8c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets_83e3c0a9-ddae-46e7-b953-07926e6a0f18" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalAbstract_70a1a708-a0c4-4993-8cf8-738b205c123c" xlink:to="loc_us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets_83e3c0a9-ddae-46e7-b953-07926e6a0f18" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalRequiredToBeWellCapitalized_7fc6fe68-1e0a-4e35-9e4c-85040797dbee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalRequiredToBeWellCapitalized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalAbstract_70a1a708-a0c4-4993-8cf8-738b205c123c" xlink:to="loc_us-gaap_CapitalRequiredToBeWellCapitalized_7fc6fe68-1e0a-4e35-9e4c-85040797dbee" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_1ecee340-4e97-4564-bdf3-e739d2183827" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalAbstract_70a1a708-a0c4-4993-8cf8-738b205c123c" xlink:to="loc_us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_1ecee340-4e97-4564-bdf3-e739d2183827" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneRiskBasedCapitalAbstract_2497ee6b-cfb8-4872-a902-3aec55783206" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneRiskBasedCapitalAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_6da3c701-b584-483d-9b12-97f7676668b3" xlink:to="loc_us-gaap_TierOneRiskBasedCapitalAbstract_2497ee6b-cfb8-4872-a902-3aec55783206" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneRiskBasedCapital_eeef7ca4-d63d-4478-ada3-a727da7eb053" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneRiskBasedCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TierOneRiskBasedCapitalAbstract_2497ee6b-cfb8-4872-a902-3aec55783206" xlink:to="loc_us-gaap_TierOneRiskBasedCapital_eeef7ca4-d63d-4478-ada3-a727da7eb053" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets_a64848a6-1d95-4208-a5d4-9fd99ef3ff97" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TierOneRiskBasedCapitalAbstract_2497ee6b-cfb8-4872-a902-3aec55783206" xlink:to="loc_us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets_a64848a6-1d95-4208-a5d4-9fd99ef3ff97" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy_52cd8b60-32a5-43ad-8fa5-5e0d7685b326" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TierOneRiskBasedCapitalAbstract_2497ee6b-cfb8-4872-a902-3aec55783206" xlink:to="loc_us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy_52cd8b60-32a5-43ad-8fa5-5e0d7685b326" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_37b2266e-75a2-4405-a925-b002410b2e8d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TierOneRiskBasedCapitalAbstract_2497ee6b-cfb8-4872-a902-3aec55783206" xlink:to="loc_us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_37b2266e-75a2-4405-a925-b002410b2e8d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized_cb5db5d9-687d-450f-85c1-a61fb8babb20" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TierOneRiskBasedCapitalAbstract_2497ee6b-cfb8-4872-a902-3aec55783206" xlink:to="loc_us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized_cb5db5d9-687d-450f-85c1-a61fb8babb20" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_aaa947e5-d06d-4b6e-b161-8edfc49c65bb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TierOneRiskBasedCapitalAbstract_2497ee6b-cfb8-4872-a902-3aec55783206" xlink:to="loc_us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_aaa947e5-d06d-4b6e-b161-8edfc49c65bb" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonEquityTierOneCapitalAbstract_5775abba-8da6-42d4-b2dd-e1825bf7ec9a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonEquityTierOneCapitalAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_6da3c701-b584-483d-9b12-97f7676668b3" xlink:to="loc_us-gaap_CommonEquityTierOneCapitalAbstract_5775abba-8da6-42d4-b2dd-e1825bf7ec9a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonEquityTierOneCapital_c47e6e6a-1605-46ce-b5bf-b1b9a1d93518" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonEquityTierOneCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommonEquityTierOneCapitalAbstract_5775abba-8da6-42d4-b2dd-e1825bf7ec9a" xlink:to="loc_us-gaap_CommonEquityTierOneCapital_c47e6e6a-1605-46ce-b5bf-b1b9a1d93518" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonEquityTierOneCapitalRatio_ffd0841e-8414-4090-ba95-b31ed1149114" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonEquityTierOneCapitalRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommonEquityTierOneCapitalAbstract_5775abba-8da6-42d4-b2dd-e1825bf7ec9a" xlink:to="loc_us-gaap_CommonEquityTierOneCapitalRatio_ffd0841e-8414-4090-ba95-b31ed1149114" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonEquityTierOneCapitalRequiredForCapitalAdequacy_f90cad9b-6a11-48e7-a60f-51dcbd6278b9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonEquityTierOneCapitalRequiredForCapitalAdequacy"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommonEquityTierOneCapitalAbstract_5775abba-8da6-42d4-b2dd-e1825bf7ec9a" xlink:to="loc_us-gaap_CommonEquityTierOneCapitalRequiredForCapitalAdequacy_f90cad9b-6a11-48e7-a60f-51dcbd6278b9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_CommonEquityTierOneCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_5487e3a8-a81b-426f-a13b-727d5fbf8bfd" xlink:href="cfb-20200930.xsd#cfb_CommonEquityTierOneCapitalRequiredForCapitalAdequacyToRiskWeightedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommonEquityTierOneCapitalAbstract_5775abba-8da6-42d4-b2dd-e1825bf7ec9a" xlink:to="loc_cfb_CommonEquityTierOneCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_5487e3a8-a81b-426f-a13b-727d5fbf8bfd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonEquityTierOneCapitalRequiredToBeWellCapitalized_0a8efd13-e13a-446c-90b0-e79d09075b24" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonEquityTierOneCapitalRequiredToBeWellCapitalized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommonEquityTierOneCapitalAbstract_5775abba-8da6-42d4-b2dd-e1825bf7ec9a" xlink:to="loc_us-gaap_CommonEquityTierOneCapitalRequiredToBeWellCapitalized_0a8efd13-e13a-446c-90b0-e79d09075b24" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_CommonEquityTierOneCapitalRequiredToBeWellCapitalizedRatio_1bc37eca-23c3-48a4-b4d2-3008ca3a7f21" xlink:href="cfb-20200930.xsd#cfb_CommonEquityTierOneCapitalRequiredToBeWellCapitalizedRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CommonEquityTierOneCapitalAbstract_5775abba-8da6-42d4-b2dd-e1825bf7ec9a" xlink:to="loc_cfb_CommonEquityTierOneCapitalRequiredToBeWellCapitalizedRatio_1bc37eca-23c3-48a4-b4d2-3008ca3a7f21" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneLeverageCapitalAbstract_8959a3d1-9fde-4d5f-a968-4af04a785592" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneLeverageCapitalAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_6da3c701-b584-483d-9b12-97f7676668b3" xlink:to="loc_us-gaap_TierOneLeverageCapitalAbstract_8959a3d1-9fde-4d5f-a968-4af04a785592" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneLeverageCapital_65001524-cb28-4242-a18c-c70f7827a4dd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneLeverageCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TierOneLeverageCapitalAbstract_8959a3d1-9fde-4d5f-a968-4af04a785592" xlink:to="loc_us-gaap_TierOneLeverageCapital_65001524-cb28-4242-a18c-c70f7827a4dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneLeverageCapitalToAverageAssets_27b9e2cf-3f13-4024-8eda-63fa506f6aa5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneLeverageCapitalToAverageAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TierOneLeverageCapitalAbstract_8959a3d1-9fde-4d5f-a968-4af04a785592" xlink:to="loc_us-gaap_TierOneLeverageCapitalToAverageAssets_27b9e2cf-3f13-4024-8eda-63fa506f6aa5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy_4418dd00-7bd7-494a-9563-f45878deb933" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TierOneLeverageCapitalAbstract_8959a3d1-9fde-4d5f-a968-4af04a785592" xlink:to="loc_us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy_4418dd00-7bd7-494a-9563-f45878deb933" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets_70b7ddb7-c13c-4109-ba3c-b1182f60bff4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TierOneLeverageCapitalAbstract_8959a3d1-9fde-4d5f-a968-4af04a785592" xlink:to="loc_us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets_70b7ddb7-c13c-4109-ba3c-b1182f60bff4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized_e5f794a4-dd00-4fb1-92bb-db87ce42cdd0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TierOneLeverageCapitalAbstract_8959a3d1-9fde-4d5f-a968-4af04a785592" xlink:to="loc_us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized_e5f794a4-dd00-4fb1-92bb-db87ce42cdd0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets_a33b9f07-4523-4c8a-8a54-efb10e16e732" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TierOneLeverageCapitalAbstract_8959a3d1-9fde-4d5f-a968-4af04a785592" xlink:to="loc_us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets_a33b9f07-4523-4c8a-8a54-efb10e16e732" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable_00cc6f5e-4083-4b42-915c-88b647d6b3e4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_6da3c701-b584-483d-9b12-97f7676668b3" xlink:to="loc_us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable_00cc6f5e-4083-4b42-915c-88b647d6b3e4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RiskWeightedAssetsCalculationMethodologyAxis_6343a643-5f96-41b6-adbf-57a559013932" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RiskWeightedAssetsCalculationMethodologyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable_00cc6f5e-4083-4b42-915c-88b647d6b3e4" xlink:to="loc_us-gaap_RiskWeightedAssetsCalculationMethodologyAxis_6343a643-5f96-41b6-adbf-57a559013932" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RiskWeightedAssetsCalculationMethodologyDomain_6343a643-5f96-41b6-adbf-57a559013932_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RiskWeightedAssetsCalculationMethodologyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RiskWeightedAssetsCalculationMethodologyAxis_6343a643-5f96-41b6-adbf-57a559013932" xlink:to="loc_us-gaap_RiskWeightedAssetsCalculationMethodologyDomain_6343a643-5f96-41b6-adbf-57a559013932_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RiskWeightedAssetsCalculationMethodologyDomain_5ea8d07e-e544-4649-8485-3b426ff79d7b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RiskWeightedAssetsCalculationMethodologyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RiskWeightedAssetsCalculationMethodologyAxis_6343a643-5f96-41b6-adbf-57a559013932" xlink:to="loc_us-gaap_RiskWeightedAssetsCalculationMethodologyDomain_5ea8d07e-e544-4649-8485-3b426ff79d7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_FullyPhaseInMember_44c1a571-7a22-415b-b858-842bba72e3a3" xlink:href="cfb-20200930.xsd#cfb_FullyPhaseInMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RiskWeightedAssetsCalculationMethodologyDomain_5ea8d07e-e544-4649-8485-3b426ff79d7b" xlink:to="loc_cfb_FullyPhaseInMember_44c1a571-7a22-415b-b858-842bba72e3a3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_9eb4eadf-5104-4ce4-aaa3-bedb583ced88" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable_00cc6f5e-4083-4b42-915c-88b647d6b3e4" xlink:to="loc_srt_ConsolidatedEntitiesAxis_9eb4eadf-5104-4ce4-aaa3-bedb583ced88" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_9eb4eadf-5104-4ce4-aaa3-bedb583ced88_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_9eb4eadf-5104-4ce4-aaa3-bedb583ced88" xlink:to="loc_srt_ConsolidatedEntitiesDomain_9eb4eadf-5104-4ce4-aaa3-bedb583ced88_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_35926972-c3c6-47f9-bfb2-0281e27f7e9a" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_9eb4eadf-5104-4ce4-aaa3-bedb583ced88" xlink:to="loc_srt_ConsolidatedEntitiesDomain_35926972-c3c6-47f9-bfb2-0281e27f7e9a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SubsidiariesMember_47188d67-21c9-4420-a50c-31f67d4371ba" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_35926972-c3c6-47f9-bfb2-0281e27f7e9a" xlink:to="loc_srt_SubsidiariesMember_47188d67-21c9-4420-a50c-31f67d4371ba" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/StockBasedCompensation" xlink:type="simple" xlink:href="cfb-20200930.xsd#StockBasedCompensation"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/StockBasedCompensation" xlink:type="extended" id="i3474b268b5274600bdac28eddeb9f70d_StockBasedCompensation"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/StockBasedCompensationTables" xlink:type="simple" xlink:href="cfb-20200930.xsd#StockBasedCompensationTables"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/StockBasedCompensationTables" xlink:type="extended" id="i987824ab9132475eacada0ccfaabd78b_StockBasedCompensationTables"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/StockBasedCompensationNarrativeDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#StockBasedCompensationNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/StockBasedCompensationNarrativeDetails" xlink:type="extended" id="i399395ef285444ffa33f2b6feffc2303_StockBasedCompensationNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_391fa06b-4258-47c8-851c-c0fab2191c67" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_2712f739-edfa-413e-aa64-21cde6698fcf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_391fa06b-4258-47c8-851c-c0fab2191c67" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_2712f739-edfa-413e-aa64-21cde6698fcf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_f8e13154-93c4-430a-9668-8549ecccdbee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_391fa06b-4258-47c8-851c-c0fab2191c67" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_f8e13154-93c4-430a-9668-8549ecccdbee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_f3c493de-4e26-4d09-a632-83cd5219c296" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_391fa06b-4258-47c8-851c-c0fab2191c67" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_f3c493de-4e26-4d09-a632-83cd5219c296" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_2478fa62-e9b7-4976-a753-f63d79ca3459" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_391fa06b-4258-47c8-851c-c0fab2191c67" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_2478fa62-e9b7-4976-a753-f63d79ca3459" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardPerformanceMetricPeriod_98a4b1f6-6210-4287-bde4-295d6e1cccbd" xlink:href="cfb-20200930.xsd#cfb_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardPerformanceMetricPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_391fa06b-4258-47c8-851c-c0fab2191c67" xlink:to="loc_cfb_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardPerformanceMetricPeriod_98a4b1f6-6210-4287-bde4-295d6e1cccbd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_d5029438-536b-4163-bd9d-0c3eb686447c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_391fa06b-4258-47c8-851c-c0fab2191c67" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_d5029438-536b-4163-bd9d-0c3eb686447c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_7a5a5f59-3c9e-49fe-88a1-c73c8c83d6c4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_391fa06b-4258-47c8-851c-c0fab2191c67" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_7a5a5f59-3c9e-49fe-88a1-c73c8c83d6c4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1d2801ed-d21e-4296-bca1-02e993452c0d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_391fa06b-4258-47c8-851c-c0fab2191c67" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1d2801ed-d21e-4296-bca1-02e993452c0d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_4d9f1a0d-798d-4b18-8cce-23332a14b5a5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1d2801ed-d21e-4296-bca1-02e993452c0d" xlink:to="loc_us-gaap_PlanNameAxis_4d9f1a0d-798d-4b18-8cce-23332a14b5a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_4d9f1a0d-798d-4b18-8cce-23332a14b5a5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_4d9f1a0d-798d-4b18-8cce-23332a14b5a5" xlink:to="loc_us-gaap_PlanNameDomain_4d9f1a0d-798d-4b18-8cce-23332a14b5a5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_76b79865-eab0-47ae-90b4-26de268a159d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_4d9f1a0d-798d-4b18-8cce-23332a14b5a5" xlink:to="loc_us-gaap_PlanNameDomain_76b79865-eab0-47ae-90b4-26de268a159d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_A2018OmnibusEquityIncentivePlanMember_1fa4427c-4a01-43bf-9a46-582c7b43fc26" xlink:href="cfb-20200930.xsd#cfb_A2018OmnibusEquityIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_76b79865-eab0-47ae-90b4-26de268a159d" xlink:to="loc_cfb_A2018OmnibusEquityIncentivePlanMember_1fa4427c-4a01-43bf-9a46-582c7b43fc26" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_99c22709-b225-483a-8321-b768dadcdc88" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1d2801ed-d21e-4296-bca1-02e993452c0d" xlink:to="loc_us-gaap_AwardTypeAxis_99c22709-b225-483a-8321-b768dadcdc88" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_99c22709-b225-483a-8321-b768dadcdc88_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_99c22709-b225-483a-8321-b768dadcdc88" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_99c22709-b225-483a-8321-b768dadcdc88_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4b6f1b6a-76a4-4ca8-bb50-617864f09296" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_99c22709-b225-483a-8321-b768dadcdc88" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4b6f1b6a-76a4-4ca8-bb50-617864f09296" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_72c02c3b-bc90-4211-93b8-3dc2c6edc042" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4b6f1b6a-76a4-4ca8-bb50-617864f09296" xlink:to="loc_us-gaap_PerformanceSharesMember_72c02c3b-bc90-4211-93b8-3dc2c6edc042" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_RestrictedStockUnitsIssuedPriorTo2019Member_fea6f38e-a969-449a-884e-0de329d7ab23" xlink:href="cfb-20200930.xsd#cfb_RestrictedStockUnitsIssuedPriorTo2019Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4b6f1b6a-76a4-4ca8-bb50-617864f09296" xlink:to="loc_cfb_RestrictedStockUnitsIssuedPriorTo2019Member_fea6f38e-a969-449a-884e-0de329d7ab23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_RestrictedStockUnitsAllOtherMember_b13a4b5d-ea20-45e4-8038-a84f81aaa0d9" xlink:href="cfb-20200930.xsd#cfb_RestrictedStockUnitsAllOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4b6f1b6a-76a4-4ca8-bb50-617864f09296" xlink:to="loc_cfb_RestrictedStockUnitsAllOtherMember_b13a4b5d-ea20-45e4-8038-a84f81aaa0d9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_a44b7ee8-08d0-4a2b-b7b6-724910164229" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4b6f1b6a-76a4-4ca8-bb50-617864f09296" xlink:to="loc_us-gaap_RestrictedStockMember_a44b7ee8-08d0-4a2b-b7b6-724910164229" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_RestrictedStockAndRestrictedStockUnitsMember_6a1e7f1f-2be5-4fb1-a446-e788e1320692" xlink:href="cfb-20200930.xsd#cfb_RestrictedStockAndRestrictedStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4b6f1b6a-76a4-4ca8-bb50-617864f09296" xlink:to="loc_cfb_RestrictedStockAndRestrictedStockUnitsMember_6a1e7f1f-2be5-4fb1-a446-e788e1320692" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_02218167-f7f5-4952-9f65-4a7e377177e9" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1d2801ed-d21e-4296-bca1-02e993452c0d" xlink:to="loc_srt_RangeAxis_02218167-f7f5-4952-9f65-4a7e377177e9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_02218167-f7f5-4952-9f65-4a7e377177e9_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_02218167-f7f5-4952-9f65-4a7e377177e9" xlink:to="loc_srt_RangeMember_02218167-f7f5-4952-9f65-4a7e377177e9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_d232d5df-746c-4c11-9062-eaed6bef28da" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_02218167-f7f5-4952-9f65-4a7e377177e9" xlink:to="loc_srt_RangeMember_d232d5df-746c-4c11-9062-eaed6bef28da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_6e663251-47d0-4d3d-9dcb-db4c954cceec" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_d232d5df-746c-4c11-9062-eaed6bef28da" xlink:to="loc_srt_MinimumMember_6e663251-47d0-4d3d-9dcb-db4c954cceec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_c37703ed-a421-4490-998e-346280258244" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_d232d5df-746c-4c11-9062-eaed6bef28da" xlink:to="loc_srt_MaximumMember_c37703ed-a421-4490-998e-346280258244" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/StockBasedCompensationTotalStockBasedCompensationDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#StockBasedCompensationTotalStockBasedCompensationDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/StockBasedCompensationTotalStockBasedCompensationDetails" xlink:type="extended" id="iedebfd97d5b0411b9ddeef425a10f01b_StockBasedCompensationTotalStockBasedCompensationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_559b024b-acf8-4758-9d00-82eb84367bf8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_7a861d4d-63c3-40d0-b317-ca768ef0497f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_559b024b-acf8-4758-9d00-82eb84367bf8" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_7a861d4d-63c3-40d0-b317-ca768ef0497f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_7131a2c3-df7e-40f2-b200-560656152a95" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_559b024b-acf8-4758-9d00-82eb84367bf8" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_7131a2c3-df7e-40f2-b200-560656152a95" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_ae92e453-f1ba-40f0-bd2f-e2337722f4aa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_7131a2c3-df7e-40f2-b200-560656152a95" xlink:to="loc_us-gaap_AwardTypeAxis_ae92e453-f1ba-40f0-bd2f-e2337722f4aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ae92e453-f1ba-40f0-bd2f-e2337722f4aa_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_ae92e453-f1ba-40f0-bd2f-e2337722f4aa" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ae92e453-f1ba-40f0-bd2f-e2337722f4aa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_caea87e0-edc1-4651-ab93-661858d5dc40" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_ae92e453-f1ba-40f0-bd2f-e2337722f4aa" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_caea87e0-edc1-4651-ab93-661858d5dc40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockAppreciationRightsSARSMember_3cd2bb76-b5ac-4930-a708-79917fd75704" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockAppreciationRightsSARSMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_caea87e0-edc1-4651-ab93-661858d5dc40" xlink:to="loc_us-gaap_StockAppreciationRightsSARSMember_3cd2bb76-b5ac-4930-a708-79917fd75704" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_9876638b-88de-4ba8-b333-5813309a8e21" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_caea87e0-edc1-4651-ab93-661858d5dc40" xlink:to="loc_us-gaap_PerformanceSharesMember_9876638b-88de-4ba8-b333-5813309a8e21" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_RestrictedStockAndRestrictedStockUnitsMember_ac0adb34-f06c-46fd-8e6b-7ded08507463" xlink:href="cfb-20200930.xsd#cfb_RestrictedStockAndRestrictedStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_caea87e0-edc1-4651-ab93-661858d5dc40" xlink:to="loc_cfb_RestrictedStockAndRestrictedStockUnitsMember_ac0adb34-f06c-46fd-8e6b-7ded08507463" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_56584f13-ea3b-40eb-a2dd-6751cf945fa1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_caea87e0-edc1-4651-ab93-661858d5dc40" xlink:to="loc_us-gaap_EmployeeStockMember_56584f13-ea3b-40eb-a2dd-6751cf945fa1" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/StockBasedCompensationStatusandChangesinPerformanceBasedAwardsDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#StockBasedCompensationStatusandChangesinPerformanceBasedAwardsDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/StockBasedCompensationStatusandChangesinPerformanceBasedAwardsDetails" xlink:type="extended" id="id6229a985ec44372acbe5bac8366ed69_StockBasedCompensationStatusandChangesinPerformanceBasedAwardsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fd9cf74f-260b-472f-b18c-33385ae56164" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_f4b4c7fa-6e29-4362-a840-5c162271769f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fd9cf74f-260b-472f-b18c-33385ae56164" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_f4b4c7fa-6e29-4362-a840-5c162271769f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_8058d931-6f54-40d3-a5d6-33c0c40684eb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_f4b4c7fa-6e29-4362-a840-5c162271769f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_8058d931-6f54-40d3-a5d6-33c0c40684eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_d6a09d97-60cc-48a2-a1b3-6fa9986efee6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_f4b4c7fa-6e29-4362-a840-5c162271769f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_d6a09d97-60cc-48a2-a1b3-6fa9986efee6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_636d0148-aca3-44be-888a-04ef11752b28" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_f4b4c7fa-6e29-4362-a840-5c162271769f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_636d0148-aca3-44be-888a-04ef11752b28" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_7f5810a2-59a0-4a75-8841-4eb2e7b7001e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_f4b4c7fa-6e29-4362-a840-5c162271769f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_7f5810a2-59a0-4a75-8841-4eb2e7b7001e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_f5849b32-1872-489d-88ad-45cf866780ce" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_b57c2870-665f-42d7-8c52-b3caaa95d6da" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fd9cf74f-260b-472f-b18c-33385ae56164" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_b57c2870-665f-42d7-8c52-b3caaa95d6da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_ea186a08-5e5c-49bc-918c-13c26e535add" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_b57c2870-665f-42d7-8c52-b3caaa95d6da" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_ea186a08-5e5c-49bc-918c-13c26e535add" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_7923319d-2170-4c83-a6bb-06806e771304" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_b57c2870-665f-42d7-8c52-b3caaa95d6da" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_7923319d-2170-4c83-a6bb-06806e771304" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_15bfaf82-3b87-445f-a49f-5c02cabd7e76" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_b57c2870-665f-42d7-8c52-b3caaa95d6da" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_15bfaf82-3b87-445f-a49f-5c02cabd7e76" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_04292b00-ee28-441b-adc4-86740d833b62" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_b57c2870-665f-42d7-8c52-b3caaa95d6da" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_04292b00-ee28-441b-adc4-86740d833b62" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_2a1b3e86-81c3-48ba-8dd0-2b1fe3648785" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_76adc721-d7c3-42a5-97dc-4e042cba9d9a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fd9cf74f-260b-472f-b18c-33385ae56164" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_76adc721-d7c3-42a5-97dc-4e042cba9d9a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_51cd9fad-dbf1-4f13-9d74-4120cc76f8e1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_76adc721-d7c3-42a5-97dc-4e042cba9d9a" xlink:to="loc_us-gaap_AwardTypeAxis_51cd9fad-dbf1-4f13-9d74-4120cc76f8e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_51cd9fad-dbf1-4f13-9d74-4120cc76f8e1_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_51cd9fad-dbf1-4f13-9d74-4120cc76f8e1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_51cd9fad-dbf1-4f13-9d74-4120cc76f8e1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9544624d-1a7e-4777-bc18-bfb44aa71d37" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_51cd9fad-dbf1-4f13-9d74-4120cc76f8e1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9544624d-1a7e-4777-bc18-bfb44aa71d37" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_fbcc2285-46ed-4b8e-9314-ee78fe391ee8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9544624d-1a7e-4777-bc18-bfb44aa71d37" xlink:to="loc_us-gaap_PerformanceSharesMember_fbcc2285-46ed-4b8e-9314-ee78fe391ee8" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/StockBasedCompensationStatusandChangesinRSUsandRSAsDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#StockBasedCompensationStatusandChangesinRSUsandRSAsDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/StockBasedCompensationStatusandChangesinRSUsandRSAsDetails" xlink:type="extended" id="iffa99c123af54346be80c08e6e845326_StockBasedCompensationStatusandChangesinRSUsandRSAsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5f28e72a-5368-4faa-aa52-b5f0070d0309" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_46b83751-d7f1-459b-83de-bb32718f5cd9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5f28e72a-5368-4faa-aa52-b5f0070d0309" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_46b83751-d7f1-459b-83de-bb32718f5cd9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_88a9fb5a-4ab6-44b4-a356-01d83141d163" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_46b83751-d7f1-459b-83de-bb32718f5cd9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_88a9fb5a-4ab6-44b4-a356-01d83141d163" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_a0c65b7d-2a49-4f0f-aaa6-1012b50943c7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_46b83751-d7f1-459b-83de-bb32718f5cd9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_a0c65b7d-2a49-4f0f-aaa6-1012b50943c7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_f3940765-fc21-402f-99a7-feae13e34101" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_46b83751-d7f1-459b-83de-bb32718f5cd9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_f3940765-fc21-402f-99a7-feae13e34101" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_73a984a9-85ac-42da-b2c9-57dbd508434a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_46b83751-d7f1-459b-83de-bb32718f5cd9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_73a984a9-85ac-42da-b2c9-57dbd508434a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_c977abe3-93f8-4805-aff3-f50a2c16e855" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_608ff1d5-f15f-419a-a100-8229b2208d2d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5f28e72a-5368-4faa-aa52-b5f0070d0309" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_608ff1d5-f15f-419a-a100-8229b2208d2d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_ca81fb0d-3593-4cf1-96a0-6bbbb994c65f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_608ff1d5-f15f-419a-a100-8229b2208d2d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_ca81fb0d-3593-4cf1-96a0-6bbbb994c65f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_d83671a2-b639-47f9-8cce-4608b5413d55" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_608ff1d5-f15f-419a-a100-8229b2208d2d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_d83671a2-b639-47f9-8cce-4608b5413d55" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_2935d872-7516-4f1b-b05b-d8fe2ada6085" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_608ff1d5-f15f-419a-a100-8229b2208d2d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_2935d872-7516-4f1b-b05b-d8fe2ada6085" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_32e62798-c755-4cdd-aec2-fca29f3ddf4f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_608ff1d5-f15f-419a-a100-8229b2208d2d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_32e62798-c755-4cdd-aec2-fca29f3ddf4f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_782ef95b-9a90-42e0-99bd-5342e8715940" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3742c086-119e-43e7-b4f8-6159f357f051" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5f28e72a-5368-4faa-aa52-b5f0070d0309" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3742c086-119e-43e7-b4f8-6159f357f051" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_92245222-b4e3-45c8-bd9b-7ebe41d11e72" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3742c086-119e-43e7-b4f8-6159f357f051" xlink:to="loc_us-gaap_AwardTypeAxis_92245222-b4e3-45c8-bd9b-7ebe41d11e72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_92245222-b4e3-45c8-bd9b-7ebe41d11e72_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_92245222-b4e3-45c8-bd9b-7ebe41d11e72" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_92245222-b4e3-45c8-bd9b-7ebe41d11e72_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1385fce3-0fbe-4558-94b1-f289d2585d80" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_92245222-b4e3-45c8-bd9b-7ebe41d11e72" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1385fce3-0fbe-4558-94b1-f289d2585d80" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_RestrictedStockAndRestrictedStockUnitsMember_234ccf3a-4a56-4906-a5d4-36d98295532c" xlink:href="cfb-20200930.xsd#cfb_RestrictedStockAndRestrictedStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1385fce3-0fbe-4558-94b1-f289d2585d80" xlink:to="loc_cfb_RestrictedStockAndRestrictedStockUnitsMember_234ccf3a-4a56-4906-a5d4-36d98295532c" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/IncomeTax" xlink:type="simple" xlink:href="cfb-20200930.xsd#IncomeTax"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/IncomeTax" xlink:type="extended" id="i08d51533a37e4352bf1fecaa03f50935_IncomeTax"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/IncomeTaxTables" xlink:type="simple" xlink:href="cfb-20200930.xsd#IncomeTaxTables"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/IncomeTaxTables" xlink:type="extended" id="ie1b4f2cc39ec4316bf0f31c97d4f09b4_IncomeTaxTables"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/IncomeTaxEffectiveIncomeTaxReconciliationDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#IncomeTaxEffectiveIncomeTaxReconciliationDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/IncomeTaxEffectiveIncomeTaxReconciliationDetails" xlink:type="extended" id="i3ed82cee76f34f1887c193f640587431_IncomeTaxEffectiveIncomeTaxReconciliationDetails"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/IncomeTaxDeferredTaxAssetsandLiabilitiesDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#IncomeTaxDeferredTaxAssetsandLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/IncomeTaxDeferredTaxAssetsandLiabilitiesDetails" xlink:type="extended" id="i66ad60539e684142b346b215d3589fcf_IncomeTaxDeferredTaxAssetsandLiabilitiesDetails"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/DisclosuresaboutFairValueofFinancialInstruments" xlink:type="simple" xlink:href="cfb-20200930.xsd#DisclosuresaboutFairValueofFinancialInstruments"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/DisclosuresaboutFairValueofFinancialInstruments" xlink:type="extended" id="i8b047bf0040142d78db1e3ecdb4183df_DisclosuresaboutFairValueofFinancialInstruments"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/DisclosuresaboutFairValueofFinancialInstrumentsTables" xlink:type="simple" xlink:href="cfb-20200930.xsd#DisclosuresaboutFairValueofFinancialInstrumentsTables"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/DisclosuresaboutFairValueofFinancialInstrumentsTables" xlink:type="extended" id="i8ce5808a9f86456eba6288b5e976542c_DisclosuresaboutFairValueofFinancialInstrumentsTables"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/DisclosuresaboutFairValueofFinancialInstrumentsNonrecurringMeasurementsDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#DisclosuresaboutFairValueofFinancialInstrumentsNonrecurringMeasurementsDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/DisclosuresaboutFairValueofFinancialInstrumentsNonrecurringMeasurementsDetails" xlink:type="extended" id="ic3e5ce8290614a5ab21bd987e17bc914_DisclosuresaboutFairValueofFinancialInstrumentsNonrecurringMeasurementsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_c9a2304c-8016-4078-8e54-5c2b32ca8cec" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ImpairedFinancingReceivableFairValueDisclosure_9b393af8-2893-4a74-8bc3-5e7799ae32d3" xlink:href="cfb-20200930.xsd#cfb_ImpairedFinancingReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_c9a2304c-8016-4078-8e54-5c2b32ca8cec" xlink:to="loc_cfb_ImpairedFinancingReceivableFairValueDisclosure_9b393af8-2893-4a74-8bc3-5e7799ae32d3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_RepossessedAssetsHeldForSaleFairValueDisclosure_c967bfc3-c8c7-4605-ab29-9dac719763ed" xlink:href="cfb-20200930.xsd#cfb_RepossessedAssetsHeldForSaleFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_c9a2304c-8016-4078-8e54-5c2b32ca8cec" xlink:to="loc_cfb_RepossessedAssetsHeldForSaleFairValueDisclosure_c967bfc3-c8c7-4605-ab29-9dac719763ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_c1aa7e60-ca62-4ad9-a4bc-8ab9faac91e8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_c9a2304c-8016-4078-8e54-5c2b32ca8cec" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_c1aa7e60-ca62-4ad9-a4bc-8ab9faac91e8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_241028e2-90e0-453e-90c0-cadf73d88712" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_c1aa7e60-ca62-4ad9-a4bc-8ab9faac91e8" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_241028e2-90e0-453e-90c0-cadf73d88712" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_241028e2-90e0-453e-90c0-cadf73d88712_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_241028e2-90e0-453e-90c0-cadf73d88712" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_241028e2-90e0-453e-90c0-cadf73d88712_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_7c47a70b-1753-4932-861f-ff2bcf924cec" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_241028e2-90e0-453e-90c0-cadf73d88712" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_7c47a70b-1753-4932-861f-ff2bcf924cec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_2f31e923-0ad2-4dc7-abd7-ea1c524c5288" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsNonrecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_7c47a70b-1753-4932-861f-ff2bcf924cec" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_2f31e923-0ad2-4dc7-abd7-ea1c524c5288" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_2ba18407-81ae-4fb3-a3d3-4f0d88c4fc1e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_c1aa7e60-ca62-4ad9-a4bc-8ab9faac91e8" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_2ba18407-81ae-4fb3-a3d3-4f0d88c4fc1e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2ba18407-81ae-4fb3-a3d3-4f0d88c4fc1e_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_2ba18407-81ae-4fb3-a3d3-4f0d88c4fc1e" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2ba18407-81ae-4fb3-a3d3-4f0d88c4fc1e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1a548cb3-07df-4aef-b07b-0ae3f6b942b1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_2ba18407-81ae-4fb3-a3d3-4f0d88c4fc1e" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1a548cb3-07df-4aef-b07b-0ae3f6b942b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_76e641a8-a008-4d14-9228-ae073f3907e8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1a548cb3-07df-4aef-b07b-0ae3f6b942b1" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_76e641a8-a008-4d14-9228-ae073f3907e8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_bae15c23-4ade-4fd2-9980-2c1757832b06" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1a548cb3-07df-4aef-b07b-0ae3f6b942b1" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_bae15c23-4ade-4fd2-9980-2c1757832b06" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_bc6ab099-047c-461f-ba3f-68828dd26c76" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1a548cb3-07df-4aef-b07b-0ae3f6b942b1" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_bc6ab099-047c-461f-ba3f-68828dd26c76" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/DisclosuresaboutFairValueofFinancialInstrumentsUnobservableInputsDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#DisclosuresaboutFairValueofFinancialInstrumentsUnobservableInputsDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/DisclosuresaboutFairValueofFinancialInstrumentsUnobservableInputsDetails" xlink:type="extended" id="i0f8934a5ec844994b137674a8ed1c129_DisclosuresaboutFairValueofFinancialInstrumentsUnobservableInputsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_2f87663b-d6d6-4aaf-a148-b65f99fc2134" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ImpairedFinancingReceivableFairValueDisclosure_9d83e27e-e4c8-49bf-a4a5-7060c1d313f6" xlink:href="cfb-20200930.xsd#cfb_ImpairedFinancingReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_2f87663b-d6d6-4aaf-a148-b65f99fc2134" xlink:to="loc_cfb_ImpairedFinancingReceivableFairValueDisclosure_9d83e27e-e4c8-49bf-a4a5-7060c1d313f6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ImpairedLoansMeasurementInput_f1a30aa6-13d0-416c-8928-51182c2f1138" xlink:href="cfb-20200930.xsd#cfb_ImpairedLoansMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_2f87663b-d6d6-4aaf-a148-b65f99fc2134" xlink:to="loc_cfb_ImpairedLoansMeasurementInput_f1a30aa6-13d0-416c-8928-51182c2f1138" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_RepossessedAssetsHeldForSaleFairValueDisclosure_c3b9186f-57e4-4198-a0fc-f79aafba876a" xlink:href="cfb-20200930.xsd#cfb_RepossessedAssetsHeldForSaleFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_2f87663b-d6d6-4aaf-a148-b65f99fc2134" xlink:to="loc_cfb_RepossessedAssetsHeldForSaleFairValueDisclosure_c3b9186f-57e4-4198-a0fc-f79aafba876a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_ForeclosedAssetsHeldForSaleMeasurementInput_cfcf92dd-d900-46d2-b50a-ce163819cd1b" xlink:href="cfb-20200930.xsd#cfb_ForeclosedAssetsHeldForSaleMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_2f87663b-d6d6-4aaf-a148-b65f99fc2134" xlink:to="loc_cfb_ForeclosedAssetsHeldForSaleMeasurementInput_cfcf92dd-d900-46d2-b50a-ce163819cd1b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_0ba3d390-9229-430a-9962-b5e1b7dc27ee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_2f87663b-d6d6-4aaf-a148-b65f99fc2134" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_0ba3d390-9229-430a-9962-b5e1b7dc27ee" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_c0890395-81b0-426c-9018-496684d84af0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_0ba3d390-9229-430a-9962-b5e1b7dc27ee" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_c0890395-81b0-426c-9018-496684d84af0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c0890395-81b0-426c-9018-496684d84af0_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_c0890395-81b0-426c-9018-496684d84af0" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c0890395-81b0-426c-9018-496684d84af0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e6e42498-18eb-46ae-81b5-5030d393867f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_c0890395-81b0-426c-9018-496684d84af0" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e6e42498-18eb-46ae-81b5-5030d393867f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_9e7263c5-3b9a-42c8-80dd-b904558f40a3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e6e42498-18eb-46ae-81b5-5030d393867f" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_9e7263c5-3b9a-42c8-80dd-b904558f40a3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_7ca1ca94-de81-46b1-94b2-ad497b3dbfad" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_0ba3d390-9229-430a-9962-b5e1b7dc27ee" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_7ca1ca94-de81-46b1-94b2-ad497b3dbfad" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_7ca1ca94-de81-46b1-94b2-ad497b3dbfad_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_7ca1ca94-de81-46b1-94b2-ad497b3dbfad" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_7ca1ca94-de81-46b1-94b2-ad497b3dbfad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_90f6d09c-25fd-4f27-8ac4-593bdd3a9ed7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_7ca1ca94-de81-46b1-94b2-ad497b3dbfad" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_90f6d09c-25fd-4f27-8ac4-593bdd3a9ed7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_1042f5ff-d1ef-4792-8cc6-521e27525f0b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_90f6d09c-25fd-4f27-8ac4-593bdd3a9ed7" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_1042f5ff-d1ef-4792-8cc6-521e27525f0b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueAxis_1d507dda-a4ba-40c9-9c9e-b22d3b72cf9d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationTechniqueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_0ba3d390-9229-430a-9962-b5e1b7dc27ee" xlink:to="loc_us-gaap_ValuationTechniqueAxis_1d507dda-a4ba-40c9-9c9e-b22d3b72cf9d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_1d507dda-a4ba-40c9-9c9e-b22d3b72cf9d_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_1d507dda-a4ba-40c9-9c9e-b22d3b72cf9d" xlink:to="loc_us-gaap_ValuationTechniqueDomain_1d507dda-a4ba-40c9-9c9e-b22d3b72cf9d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_e85d5138-231d-409e-a29b-c6b3c975f15a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_1d507dda-a4ba-40c9-9c9e-b22d3b72cf9d" xlink:to="loc_us-gaap_ValuationTechniqueDomain_e85d5138-231d-409e-a29b-c6b3c975f15a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketApproachValuationTechniqueMember_4d712c95-915e-40d6-9cd1-3f738a52bce2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MarketApproachValuationTechniqueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_e85d5138-231d-409e-a29b-c6b3c975f15a" xlink:to="loc_us-gaap_MarketApproachValuationTechniqueMember_4d712c95-915e-40d6-9cd1-3f738a52bce2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_a11a7c60-b4f0-42de-b789-272489b8604d" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_0ba3d390-9229-430a-9962-b5e1b7dc27ee" xlink:to="loc_srt_RangeAxis_a11a7c60-b4f0-42de-b789-272489b8604d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_a11a7c60-b4f0-42de-b789-272489b8604d_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_a11a7c60-b4f0-42de-b789-272489b8604d" xlink:to="loc_srt_RangeMember_a11a7c60-b4f0-42de-b789-272489b8604d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_3c1a4b0a-2ba2-4b2c-939a-44034231771d" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_a11a7c60-b4f0-42de-b789-272489b8604d" xlink:to="loc_srt_RangeMember_3c1a4b0a-2ba2-4b2c-939a-44034231771d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_1d216915-cc2e-44f7-9470-9e864bc0ed2e" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3c1a4b0a-2ba2-4b2c-939a-44034231771d" xlink:to="loc_srt_MinimumMember_1d216915-cc2e-44f7-9470-9e864bc0ed2e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_050b80ec-373a-40ee-b5af-53ffd4c82d8d" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3c1a4b0a-2ba2-4b2c-939a-44034231771d" xlink:to="loc_srt_MaximumMember_050b80ec-373a-40ee-b5af-53ffd4c82d8d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_WeightedAverageMember_7d61beb2-cba4-48f5-a1a9-c35c618941b2" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_WeightedAverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3c1a4b0a-2ba2-4b2c-939a-44034231771d" xlink:to="loc_srt_WeightedAverageMember_7d61beb2-cba4-48f5-a1a9-c35c618941b2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_e9322911-ea27-416d-9fe5-396db4bda019" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_0ba3d390-9229-430a-9962-b5e1b7dc27ee" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_e9322911-ea27-416d-9fe5-396db4bda019" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_e9322911-ea27-416d-9fe5-396db4bda019_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_e9322911-ea27-416d-9fe5-396db4bda019" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_e9322911-ea27-416d-9fe5-396db4bda019_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_0b543e39-b45e-446d-8745-0023dee47c98" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_e9322911-ea27-416d-9fe5-396db4bda019" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_0b543e39-b45e-446d-8745-0023dee47c98" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_e909233b-9d6b-4270-afaa-092559de2ab2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsNonrecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_0b543e39-b45e-446d-8745-0023dee47c98" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_e909233b-9d6b-4270-afaa-092559de2ab2" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/DisclosuresaboutFairValueofFinancialInstrumentsFairValueofFinancialInstrumentsDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#DisclosuresaboutFairValueofFinancialInstrumentsFairValueofFinancialInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/DisclosuresaboutFairValueofFinancialInstrumentsFairValueofFinancialInstrumentsDetails" xlink:type="extended" id="i63dbad67c2944b8aac3400ec6fe04169_DisclosuresaboutFairValueofFinancialInstrumentsFairValueofFinancialInstrumentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_37180eb9-90a5-4eaa-9617-89f3375a2bc4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_fdf84a5a-58dc-4808-8137-d96d0560b667" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_37180eb9-90a5-4eaa-9617-89f3375a2bc4" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_fdf84a5a-58dc-4808-8137-d96d0560b667" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_3e6f8707-14e4-41d1-9040-8876f6c85455" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_fdf84a5a-58dc-4808-8137-d96d0560b667" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_3e6f8707-14e4-41d1-9040-8876f6c85455" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_353475b9-dbf1-4ff7-97c6-1ad0fec20920" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_fdf84a5a-58dc-4808-8137-d96d0560b667" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_353475b9-dbf1-4ff7-97c6-1ad0fec20920" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansReceivableFairValueDisclosure_af5d76cc-3642-4bbd-8c80-ca6de7a5e7ea" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoansReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_fdf84a5a-58dc-4808-8137-d96d0560b667" xlink:to="loc_us-gaap_LoansReceivableFairValueDisclosure_af5d76cc-3642-4bbd-8c80-ca6de7a5e7ea" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiRestricted_b6068b79-5bcb-485d-8333-507af0108589" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquitySecuritiesFvNiRestricted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_fdf84a5a-58dc-4808-8137-d96d0560b667" xlink:to="loc_us-gaap_EquitySecuritiesFvNiRestricted_b6068b79-5bcb-485d-8333-507af0108589" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_InterestReceivableFairValueDisclosure_fd3f3c43-50cf-45d5-bd18-0b2db9c5ae87" xlink:href="cfb-20200930.xsd#cfb_InterestReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_fdf84a5a-58dc-4808-8137-d96d0560b667" xlink:to="loc_cfb_InterestReceivableFairValueDisclosure_fd3f3c43-50cf-45d5-bd18-0b2db9c5ae87" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_57fcb058-e69b-450d-ba02-070967c25dc1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_fdf84a5a-58dc-4808-8137-d96d0560b667" xlink:to="loc_us-gaap_DerivativeAssets_57fcb058-e69b-450d-ba02-070967c25dc1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_6c3ee73b-f789-429f-8102-0351c9f416b2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_fdf84a5a-58dc-4808-8137-d96d0560b667" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_6c3ee73b-f789-429f-8102-0351c9f416b2" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_cbfb9839-17ad-46cc-ba6b-7b9f5a63bbd1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_37180eb9-90a5-4eaa-9617-89f3375a2bc4" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_cbfb9839-17ad-46cc-ba6b-7b9f5a63bbd1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepositsFairValueDisclosure_0c92be29-f475-489d-bd81-f9c4b88a9bcf" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DepositsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_cbfb9839-17ad-46cc-ba6b-7b9f5a63bbd1" xlink:to="loc_us-gaap_DepositsFairValueDisclosure_0c92be29-f475-489d-bd81-f9c4b88a9bcf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalFundsPurchasedAndSecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure_572a01ed-ce76-4062-933b-343d69eea1da" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FederalFundsPurchasedAndSecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_cbfb9839-17ad-46cc-ba6b-7b9f5a63bbd1" xlink:to="loc_us-gaap_FederalFundsPurchasedAndSecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure_572a01ed-ce76-4062-933b-343d69eea1da" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure_05b3e8c9-2bda-4e11-bd56-9f41aaef0365" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_cbfb9839-17ad-46cc-ba6b-7b9f5a63bbd1" xlink:to="loc_us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure_05b3e8c9-2bda-4e11-bd56-9f41aaef0365" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_OtherBorrowingsFairValueDisclosure_62ed2889-2275-4ef9-be0d-b04ec868423a" xlink:href="cfb-20200930.xsd#cfb_OtherBorrowingsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_cbfb9839-17ad-46cc-ba6b-7b9f5a63bbd1" xlink:to="loc_cfb_OtherBorrowingsFairValueDisclosure_62ed2889-2275-4ef9-be0d-b04ec868423a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_InterestPayableFairValueDisclosure_4bcf84bb-25fd-4293-9087-0238cdb9c579" xlink:href="cfb-20200930.xsd#cfb_InterestPayableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_cbfb9839-17ad-46cc-ba6b-7b9f5a63bbd1" xlink:to="loc_cfb_InterestPayableFairValueDisclosure_4bcf84bb-25fd-4293-9087-0238cdb9c579" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_da5062da-0ba2-4539-84dd-e8254c7f8254" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_cbfb9839-17ad-46cc-ba6b-7b9f5a63bbd1" xlink:to="loc_us-gaap_DerivativeLiabilities_da5062da-0ba2-4539-84dd-e8254c7f8254" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialLiabilitiesFairValueDisclosure_b2d46d5c-bbc9-4eee-b042-1cc98709a509" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialLiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_cbfb9839-17ad-46cc-ba6b-7b9f5a63bbd1" xlink:to="loc_us-gaap_FinancialLiabilitiesFairValueDisclosure_b2d46d5c-bbc9-4eee-b042-1cc98709a509" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_fa26ca76-6715-49a3-a3ca-3f7bf27a1eb4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_37180eb9-90a5-4eaa-9617-89f3375a2bc4" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_fa26ca76-6715-49a3-a3ca-3f7bf27a1eb4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_4a7d5127-8a84-42c2-ad0d-4a48c10c3208" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_fa26ca76-6715-49a3-a3ca-3f7bf27a1eb4" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_4a7d5127-8a84-42c2-ad0d-4a48c10c3208" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_4a7d5127-8a84-42c2-ad0d-4a48c10c3208_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_4a7d5127-8a84-42c2-ad0d-4a48c10c3208" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_4a7d5127-8a84-42c2-ad0d-4a48c10c3208_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_1a4f0f58-cdc4-4e85-b587-d469999ed599" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_4a7d5127-8a84-42c2-ad0d-4a48c10c3208" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_1a4f0f58-cdc4-4e85-b587-d469999ed599" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_53c1b27a-8f8b-4618-ace4-6d2938266f0d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_1a4f0f58-cdc4-4e85-b587-d469999ed599" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_53c1b27a-8f8b-4618-ace4-6d2938266f0d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_9b72b695-436a-4e3e-aeef-59fe39279fad" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_1a4f0f58-cdc4-4e85-b587-d469999ed599" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_9b72b695-436a-4e3e-aeef-59fe39279fad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_b77c96cf-6b3e-433e-866e-a49877d92767" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_1a4f0f58-cdc4-4e85-b587-d469999ed599" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_b77c96cf-6b3e-433e-866e-a49877d92767" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_15da0639-22e1-44c3-b3ec-c35b82df497a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_fa26ca76-6715-49a3-a3ca-3f7bf27a1eb4" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_15da0639-22e1-44c3-b3ec-c35b82df497a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_15da0639-22e1-44c3-b3ec-c35b82df497a_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_15da0639-22e1-44c3-b3ec-c35b82df497a" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_15da0639-22e1-44c3-b3ec-c35b82df497a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2959ae03-553b-4a70-b2f2-59310da5784a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_15da0639-22e1-44c3-b3ec-c35b82df497a" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2959ae03-553b-4a70-b2f2-59310da5784a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_1cbb6717-5eb7-4c71-9ca2-904229264df0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2959ae03-553b-4a70-b2f2-59310da5784a" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_1cbb6717-5eb7-4c71-9ca2-904229264df0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_d74022a5-61d1-401b-8b6a-6810820e591c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2959ae03-553b-4a70-b2f2-59310da5784a" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_d74022a5-61d1-401b-8b6a-6810820e591c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_16c25a9f-58c8-465c-ac12-9456eefc8928" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2959ae03-553b-4a70-b2f2-59310da5784a" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_16c25a9f-58c8-465c-ac12-9456eefc8928" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/CommitmentsandCreditRisk" xlink:type="simple" xlink:href="cfb-20200930.xsd#CommitmentsandCreditRisk"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/CommitmentsandCreditRisk" xlink:type="extended" id="i7697e381ec3641a4992cbcf2bb66c796_CommitmentsandCreditRisk"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/CommitmentsandCreditRiskTables" xlink:type="simple" xlink:href="cfb-20200930.xsd#CommitmentsandCreditRiskTables"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/CommitmentsandCreditRiskTables" xlink:type="extended" id="ib0246f39f5b64a3e9baec462ded5072d_CommitmentsandCreditRiskTables"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/CommitmentsandCreditRiskDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#CommitmentsandCreditRiskDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/CommitmentsandCreditRiskDetails" xlink:type="extended" id="i29cf12a5e4ab4b0fa30d81fcd1153af9_CommitmentsandCreditRiskDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_e99f479e-62fe-40e8-823f-140248e270ba" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability_7736b724-e179-41a3-a7ab-e4ee72ea5961" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_e99f479e-62fe-40e8-823f-140248e270ba" xlink:to="loc_us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability_7736b724-e179-41a3-a7ab-e4ee72ea5961" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_3b6889d6-2a70-45d2-a0d7-48516d9c1ada" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_e99f479e-62fe-40e8-823f-140248e270ba" xlink:to="loc_us-gaap_LossContingenciesTable_3b6889d6-2a70-45d2-a0d7-48516d9c1ada" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_0d27b0f8-5488-4452-9a68-566794f2dde6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_3b6889d6-2a70-45d2-a0d7-48516d9c1ada" xlink:to="loc_us-gaap_FinancialInstrumentAxis_0d27b0f8-5488-4452-9a68-566794f2dde6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_0d27b0f8-5488-4452-9a68-566794f2dde6_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_0d27b0f8-5488-4452-9a68-566794f2dde6" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_0d27b0f8-5488-4452-9a68-566794f2dde6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b1b1558f-facd-4d72-920a-738363c9a162" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_0d27b0f8-5488-4452-9a68-566794f2dde6" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b1b1558f-facd-4d72-920a-738363c9a162" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanOriginationCommitmentsMember_20650e25-8de8-402c-8e06-a50a2603d0ca" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoanOriginationCommitmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b1b1558f-facd-4d72-920a-738363c9a162" xlink:to="loc_us-gaap_LoanOriginationCommitmentsMember_20650e25-8de8-402c-8e06-a50a2603d0ca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StandbyLettersOfCreditMember_8f3eaea8-7502-4934-b325-0b12c0b99839" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StandbyLettersOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b1b1558f-facd-4d72-920a-738363c9a162" xlink:to="loc_us-gaap_StandbyLettersOfCreditMember_8f3eaea8-7502-4934-b325-0b12c0b99839" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_fcc9b2e5-7c17-4d9d-8b5b-64b999a3b573" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b1b1558f-facd-4d72-920a-738363c9a162" xlink:to="loc_us-gaap_LineOfCreditMember_fcc9b2e5-7c17-4d9d-8b5b-64b999a3b573" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cfb_FutureLeaseCommitmentMember_072983ce-0915-40a9-827e-2cd8dd8ac362" xlink:href="cfb-20200930.xsd#cfb_FutureLeaseCommitmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b1b1558f-facd-4d72-920a-738363c9a162" xlink:to="loc_cfb_FutureLeaseCommitmentMember_072983ce-0915-40a9-827e-2cd8dd8ac362" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/LegalandRegulatoryProceedings" xlink:type="simple" xlink:href="cfb-20200930.xsd#LegalandRegulatoryProceedings"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/LegalandRegulatoryProceedings" xlink:type="extended" id="i98045389138b4638ae841c6c481458f1_LegalandRegulatoryProceedings"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/SubsequentEvents" xlink:type="simple" xlink:href="cfb-20200930.xsd#SubsequentEvents"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/SubsequentEvents" xlink:type="extended" id="i5d8cef0fceb54e77a66ab515b3a42ba0_SubsequentEvents"/>
  <link:roleRef roleURI="http://www.crossfirstbank.com/role/SubsequentEventsDetails" xlink:type="simple" xlink:href="cfb-20200930.xsd#SubsequentEventsDetails"/>
  <link:definitionLink xlink:role="http://www.crossfirstbank.com/role/SubsequentEventsDetails" xlink:type="extended" id="i43c6f38369ba4cfd850ee2d2a822c934_SubsequentEventsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_554095ef-a43c-461c-9778-b54cc114a1fd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_920859c7-6864-4da1-b76a-cd9514e9d2bc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_554095ef-a43c-461c-9778-b54cc114a1fd" xlink:to="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_920859c7-6864-4da1-b76a-cd9514e9d2bc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_2636a978-7e55-47dd-98b3-7d0518f27e71" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_554095ef-a43c-461c-9778-b54cc114a1fd" xlink:to="loc_us-gaap_SubsequentEventTable_2636a978-7e55-47dd-98b3-7d0518f27e71" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_62451d9c-863c-4c72-9de3-28f700aa8383" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_2636a978-7e55-47dd-98b3-7d0518f27e71" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_62451d9c-863c-4c72-9de3-28f700aa8383" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_62451d9c-863c-4c72-9de3-28f700aa8383_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_62451d9c-863c-4c72-9de3-28f700aa8383" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_62451d9c-863c-4c72-9de3-28f700aa8383_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_febca39b-250f-489c-8f12-7ac06ed8f2b1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_62451d9c-863c-4c72-9de3-28f700aa8383" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_febca39b-250f-489c-8f12-7ac06ed8f2b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_5582d155-57ae-44a0-8cd0-47137a931f85" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_febca39b-250f-489c-8f12-7ac06ed8f2b1" xlink:to="loc_us-gaap_SubsequentEventMember_5582d155-57ae-44a0-8cd0-47137a931f85" xlink:type="arc" order="0"/>
  </link:definitionLink>
</link:linkbase>
