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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019f8fa2-e9ab-7ed4-8f54-740986798376,g:dfb63bb4-c878-4a39-8f8f-fbf3376bc941-->
<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.midlandsb.com/role/Cover" xlink:type="simple" xlink:href="msbi-20260723.xsd#Cover"/>
  <link:definitionLink xlink:role="http://www.midlandsb.com/role/Cover" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_019f8fa2-e9ab-764b-bdf2-60b7fb72a036" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_019f8fa2-e9ab-75e6-9cab-d66228a50b3e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_019f8fa2-e9ab-764b-bdf2-60b7fb72a036" xlink:to="loc_dei_DocumentInformationTable_019f8fa2-e9ab-75e6-9cab-d66228a50b3e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019f8fa2-e9ab-738f-85a7-cea4bd54ab77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_019f8fa2-e9ab-75e6-9cab-d66228a50b3e" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019f8fa2-e9ab-738f-85a7-cea4bd54ab77" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019f8fa2-e9ab-738f-85a7-cea4bd54ab77_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019f8fa2-e9ab-738f-85a7-cea4bd54ab77" xlink:to="loc_us-gaap_ClassOfStockDomain_019f8fa2-e9ab-738f-85a7-cea4bd54ab77_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019f8fa2-e9ab-773e-b20c-1609e7c6c612" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019f8fa2-e9ab-738f-85a7-cea4bd54ab77" xlink:to="loc_us-gaap_ClassOfStockDomain_019f8fa2-e9ab-773e-b20c-1609e7c6c612" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019f8fa2-e9ab-7511-85de-a5d9d34ad4eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019f8fa2-e9ab-773e-b20c-1609e7c6c612" xlink:to="loc_us-gaap_CommonStockMember_019f8fa2-e9ab-7511-85de-a5d9d34ad4eb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_msbi_DepositarySharesMember_019f8fa2-e9ab-7104-99cf-d47f97e24692" xlink:href="msbi-20260723.xsd#msbi_DepositarySharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_019f8fa2-e9ab-773e-b20c-1609e7c6c612" xlink:to="loc_msbi_DepositarySharesMember_019f8fa2-e9ab-7104-99cf-d47f97e24692" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019f8fa2-e9ab-7a81-bbeb-2f0922621379" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8fa2-e9ab-764b-bdf2-60b7fb72a036" xlink:to="loc_dei_Security12bTitle_019f8fa2-e9ab-7a81-bbeb-2f0922621379" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019f8fa2-e9ab-7c26-8761-ed98d6b1900e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8fa2-e9ab-764b-bdf2-60b7fb72a036" xlink:to="loc_dei_TradingSymbol_019f8fa2-e9ab-7c26-8761-ed98d6b1900e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019f8fa2-e9ab-7a7c-995a-2d0f9fb695e4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019f8fa2-e9ab-764b-bdf2-60b7fb72a036" xlink:to="loc_dei_SecurityExchangeName_019f8fa2-e9ab-7a7c-995a-2d0f9fb695e4" xlink:type="arc" order="2"/>
  </link:definitionLink>
</link:linkbase>
