content: <?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
    <headerData>
      <submissionType>144</submissionType>
      <filerInfo>
        <filer>
          <filerCredentials>
            <cik>0001906662</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>Hartlieb James Edward</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Officer</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>CAPIS</name>
          <address>
            <com:street1>1700 Pacific Avenue</com:street1>
            <com:street2>Suite 1100</com:street2>
            <com:city>Dallas</com:city>
            <com:stateOrCountry>TX</com:stateOrCountry>
            <com:zipCode>75201</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>6334</noOfUnitsSold>
        <aggregateMarketValue>280279.50</aggregateMarketValue>
        <noOfUnitsOutstanding>8295017</noOfUnitsOutstanding>
        <approxSaleDate>10/31/2024</approxSaleDate>
        <securitiesExchangeName>NASDAQ</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/16/2017</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>389</amountOfSecuritiesAcquired>
        <paymentDate>08/16/2017</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>389</amountOfSecuritiesAcquired>
        <paymentDate>08/16/2017</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>372</amountOfSecuritiesAcquired>
        <paymentDate>08/16/2018</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>372</amountOfSecuritiesAcquired>
        <paymentDate>08/16/2018</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>372</amountOfSecuritiesAcquired>
        <paymentDate>08/16/2018</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>403</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2019</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>403</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2019</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>403</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2019</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>338</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2020</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>338</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2020</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>318</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2020</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/16/2021</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>439</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2021</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/16/2021</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>439</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2021</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/16/2021</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>412</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2021</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/16/2021</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>187</amountOfSecuritiesAcquired>
        <paymentDate>08/16/2021</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>08/16/2021</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>185</amountOfSecuritiesAcquired>
        <paymentDate>08/16/2021</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>203</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2022</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>191</amountOfSecuritiesAcquired>
        <paymentDate>02/16/2022</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>02/20/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Unit Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>191</amountOfSecuritiesAcquired>
        <paymentDate>02/20/2024</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>10/30/2024</noticeDate>
        <signature>James E. Hartlieb</signature>
      </noticeSignature>
    </formData>
  </edgarSubmission>
metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 12434}]
text: 144
  0001906662
  XXXXXXXX
  LIVE
  0001521951
  FIRST BUSINESS FINANCIAL SERVICES, INC.
  001-34095
  401 CHARMANY DRIVE
  MADISON
  WI
  53719
  608-238-8008
  Hartlieb James Edward
  Officer
  Common
  CAPIS
  1700 Pacific Avenue
  Suite 1100
  Dallas
  TX
  75201
  6334
  280279.50
  8295017
  10/31/2024
  NASDAQ
  Common
  08/16/2017
  Restricted Stock Vesting
  Issuer
  N
  389
  08/16/2017
  Compensation
  Common
  08/16/2017
  Restricted Stock Vesting
  Issuer
  N
  389
  08/16/2017
  Compensation
  Common
  08/16/2018
  Restricted Stock Vesting
  Issuer
  N
  372
  08/16/2018
  Compensation
  Common
  08/16/2018
  Restricted Stock Vesting
  Issuer
  N
  372
  08/16/2018
  Compensation
  Common
  08/16/2018
  Restricted Stock Vesting
  Issuer
  N
  372
  08/16/2018
  Compensation
  Common
  02/16/2019
  Restricted Stock Vesting
  Issuer
  N
  403
  02/16/2019
  Compensation
  Common
  02/16/2019
  Restricted Stock Vesting
  Issuer
  N
  403
  02/16/2019
  Compensation
  Common
  02/16/2019
  Restricted Stock Vesting
  Issuer
  N
  403
  02/16/2019
  Compensation
  Common
  02/16/2020
  Restricted Stock Vesting
  Issuer
  N
  338
  02/16/2020
  Compensation
  Common
  02/16/2020
  Restricted Stock Vesting
  Issuer
  N
  338
  02/16/2020
  Compensation
  Common
  02/16/2020
  Restricted Stock Vesting
  Issuer
  N
  318
  02/16/2020
  Compensation
  Common
  02/16/2021
  Restricted Stock Vesting
  Issuer
  N
  439
  02/16/2021
  Compensation
  Common
  02/16/2021
  Restricted Stock Vesting
  Issuer
  N
  439
  02/16/2021
  Compensation
  Common
  02/16/2021
  Restricted Stock Vesting
  Issuer
  N
  412
  02/16/2021
  Compensation
  Common
  08/16/2021
  Restricted Stock Vesting
  Issuer
  N
  187
  08/16/2021
  Compensation
  Common
  08/16/2021
  Restricted Stock Vesting
  Issuer
  N
  185
  08/16/2021
  Compensation
  Common
  02/16/2022
  Restricted Stock Vesting
  Issuer
  N
  203
  02/16/2022
  Compensation
  Common
  02/16/2022
  Restricted Stock Vesting
  Issuer
  N
  191
  02/16/2022
  Compensation
  Common
  02/20/2024
  Restricted Stock Unit Vesting
  Issuer
  N
  191
  02/20/2024
  Compensation
  Y
  10/30/2024
  James E. Hartlieb