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      <submissionType>144</submissionType>
      <filerInfo>
        <filer>
          <filerCredentials>
            <cik>0001311295</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
      </filerInfo>
    </headerData>
    <formData>
      <issuerInfo>
        <issuerCik>0001521951</issuerCik>
        <issuerName>FIRST BUSINESS FINANCIAL SERVICES, INC.</issuerName>
        <secFileNumber>001-34095</secFileNumber>
        <issuerAddress>
          <com:street1>401 CHARMANY DRIVE</com:street1>
          <com:city>MADISON</com:city>
          <com:stateOrCountry>WI</com:stateOrCountry>
          <com:zipCode>53719</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>608-238-8008</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>CHAMBAS COREY A</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Officer</relationshipToIssuer>
          <relationshipToIssuer>Director</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>Keefe, Bruyette &amp; Woods (A Stifel Company)</name>
          <address>
            <com:street1>787 Seventh Avenue</com:street1>
            <com:street2>4th Floor</com:street2>
            <com:city>New York</com:city>
            <com:stateOrCountry>NY</com:stateOrCountry>
            <com:zipCode>10019</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>40000</noOfUnitsSold>
        <aggregateMarketValue>1776800.00</aggregateMarketValue>
        <noOfUnitsOutstanding>8295017</noOfUnitsOutstanding>
        <approxSaleDate>11/07/2024</approxSaleDate>
        <securitiesExchangeName>Nasdaq</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>04/18/2023</acquiredDate>
        <natureOfAcquisitionTransaction>Performance Restricted Stock Unit Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>6875</amountOfSecuritiesAcquired>
        <paymentDate>04/18/2023</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>04/18/2022</acquiredDate>
        <natureOfAcquisitionTransaction>Performance Restricted Stock Unit Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>8559</amountOfSecuritiesAcquired>
        <paymentDate>04/18/2022</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/16/2022</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>779</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2022</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>3380</securitiesClassTitle>
        <acquiredDate>02/16/2021</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>3380</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2021</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/16/2020</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>3276</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2020</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/16/2019</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>2885</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2019</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/16/2018</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>1999</amountOfSecuritiesAcquired>
        <paymentDate>08/16/2018</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/16/2017</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>4194</amountOfSecuritiesAcquired>
        <paymentDate>08/16/2017</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/31/2015</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>3565</amountOfSecuritiesAcquired>
        <paymentDate>08/31/2015</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/16/2014</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>2146</amountOfSecuritiesAcquired>
        <paymentDate>08/16/2014</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/16/2013</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>1045</amountOfSecuritiesAcquired>
        <paymentDate>08/16/2013</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/16/2012</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>1297</amountOfSecuritiesAcquired>
        <paymentDate>08/16/2012</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>11/07/2024</noticeDate>
        <signature>Corey A. Chambas</signature>
      </noticeSignature>
    </formData>
  </edgarSubmission>
metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 8811}]
text: 144
  0001311295
  XXXXXXXX
  LIVE
  0001521951
  FIRST BUSINESS FINANCIAL SERVICES, INC.
  001-34095
  401 CHARMANY DRIVE
  MADISON
  WI
  53719
  608-238-8008
  CHAMBAS COREY A
  Officer
  Director
  Common
  Keefe, Bruyette & Woods (A Stifel Company)
  787 Seventh Avenue
  4th Floor
  New York
  NY
  10019
  40000
  1776800.00
  8295017
  11/07/2024
  Nasdaq
  Common
  04/18/2023
  Performance Restricted Stock Unit Vesting
  Issuer
  N
  6875
  04/18/2023
  Compensation
  Common
  04/18/2022
  Performance Restricted Stock Unit Vesting
  Issuer
  N
  8559
  04/18/2022
  Compensation
  Common
  02/16/2022
  Restricted Stock Vesting
  Issuer
  N
  779
  02/16/2022
  Compensation
  3380
  02/16/2021
  Restricted Stock Vesting
  Issuer
  N
  3380
  02/16/2021
  Compensation
  Common
  02/16/2020
  Restricted Stock Vesting
  Issuer
  N
  3276
  02/16/2020
  Compensation
  Common
  02/16/2019
  Restricted Stock Vesting
  Issuer
  N
  2885
  02/16/2019
  Compensation
  Common
  08/16/2018
  Restricted Stock Vesting
  Issuer
  N
  1999
  08/16/2018
  Compensation
  Common
  08/16/2017
  Restricted Stock Vesting
  Issuer
  N
  4194
  08/16/2017
  Compensation
  Common
  08/31/2015
  Restricted Stock Vesting
  Issuer
  N
  3565
  08/31/2015
  Compensation
  Common
  08/16/2014
  Restricted Stock Vesting
  Issuer
  N
  2146
  08/16/2014
  Compensation
  Common
  08/16/2013
  Restricted Stock Vesting
  Issuer
  N
  1045
  08/16/2013
  Compensation
  Common
  08/16/2012
  Restricted Stock Vesting
  Issuer
  N
  1297
  08/16/2012
  Compensation
  Y
  11/07/2024
  Corey A. Chambas