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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019ead9f-28b3-7b25-a5b8-beb9dc46095e,g:07077a21-1e2d-46e6-9423-5d118d9f29d0-->
<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.hagerty.com/role/Cover" xlink:type="simple" xlink:href="hgty-20260609.xsd#Cover"/>
  <link:definitionLink xlink:role="http://www.hagerty.com/role/Cover" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_019ead9f-28b3-72f0-ae0c-6e8af1b9acf9" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_EntitiesTable_019ead9f-28b3-72f0-ae0c-6e8af1b9acf9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019ead9f-28b3-7a43-872d-c804823e8127" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_019ead9f-28b3-72f0-ae0c-6e8af1b9acf9" xlink:to="loc_dei_LegalEntityAxis_019ead9f-28b3-7a43-872d-c804823e8127" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019ead9f-28b3-7a43-872d-c804823e8127_default" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019ead9f-28b3-7a43-872d-c804823e8127" xlink:to="loc_dei_EntityDomain_019ead9f-28b3-7a43-872d-c804823e8127_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019ead9f-28b3-7524-b1e5-4d81c3b1a3c1" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019ead9f-28b3-7a43-872d-c804823e8127" xlink:to="loc_dei_EntityDomain_019ead9f-28b3-7524-b1e5-4d81c3b1a3c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_019ead9f-28b3-7c8f-bcee-ac93076a2cd0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_019ead9f-28b3-72f0-ae0c-6e8af1b9acf9" xlink:to="loc_us-gaap_StatementClassOfStockAxis_019ead9f-28b3-7c8f-bcee-ac93076a2cd0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019ead9f-28b3-7c8f-bcee-ac93076a2cd0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019ead9f-28b3-7c8f-bcee-ac93076a2cd0" xlink:to="loc_us-gaap_ClassOfStockDomain_019ead9f-28b3-7c8f-bcee-ac93076a2cd0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_019ead9f-28b3-7491-ab43-14d837328508" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_019ead9f-28b3-7c8f-bcee-ac93076a2cd0" xlink:to="loc_us-gaap_ClassOfStockDomain_019ead9f-28b3-7491-ab43-14d837328508" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019ead9f-28b3-7c3e-b986-321e07f8c378" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_DocumentType_019ead9f-28b3-7c3e-b986-321e07f8c378" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019ead9f-28b3-7f87-bd47-cabec939130e" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_DocumentPeriodEndDate_019ead9f-28b3-7f87-bd47-cabec939130e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019ead9f-28b3-7d70-902f-7d4f949d1b48" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_EntityRegistrantName_019ead9f-28b3-7d70-902f-7d4f949d1b48" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019ead9f-28b3-74d3-a0a8-f1cd9dff3171" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019ead9f-28b3-74d3-a0a8-f1cd9dff3171" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019ead9f-28b3-74b3-ba26-2b9b38c0046d" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_EntityFileNumber_019ead9f-28b3-74b3-ba26-2b9b38c0046d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019ead9f-28b3-75d4-aa6d-08f4a30549f3" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_EntityAddressAddressLine1_019ead9f-28b3-75d4-aa6d-08f4a30549f3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019ead9f-28b3-7faa-8edd-ccc8ad951af8" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_EntityAddressCityOrTown_019ead9f-28b3-7faa-8edd-ccc8ad951af8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019ead9f-28b3-79af-bd00-7700ef2a898f" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_EntityAddressStateOrProvince_019ead9f-28b3-79af-bd00-7700ef2a898f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019ead9f-28b3-7489-89da-a6c33a2530f8" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_EntityAddressPostalZipCode_019ead9f-28b3-7489-89da-a6c33a2530f8" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019ead9f-28b3-72f1-aed1-1f8179f32beb" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_CityAreaCode_019ead9f-28b3-72f1-aed1-1f8179f32beb" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019ead9f-28b3-7675-8f74-14fbdf8fd937" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_LocalPhoneNumber_019ead9f-28b3-7675-8f74-14fbdf8fd937" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_019ead9f-28b3-777a-8371-cf55068311fa" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_WrittenCommunications_019ead9f-28b3-777a-8371-cf55068311fa" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_019ead9f-28b3-7535-8809-8eeba73b851d" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_SolicitingMaterial_019ead9f-28b3-7535-8809-8eeba73b851d" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_019ead9f-28b3-706c-b206-2f88410b9f40" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_PreCommencementTenderOffer_019ead9f-28b3-706c-b206-2f88410b9f40" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_019ead9f-28b3-716a-b50a-1eca56473c12" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_019ead9f-28b3-716a-b50a-1eca56473c12" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019ead9f-28b3-7b77-b4d7-4b7fb07cc7c5" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_EntityEmergingGrowthCompany_019ead9f-28b3-7b77-b4d7-4b7fb07cc7c5" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityExTransitionPeriod_019ead9f-28b3-79e7-b0a1-0862912225d3" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityExTransitionPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_EntityExTransitionPeriod_019ead9f-28b3-79e7-b0a1-0862912225d3" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019ead9f-28b3-72e7-9b86-8b1d41ce23c3" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_EntityCentralIndexKey_019ead9f-28b3-72e7-9b86-8b1d41ce23c3" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019ead9f-28b3-7c52-b4c1-958412725f2a" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_AmendmentFlag_019ead9f-28b3-7c52-b4c1-958412725f2a" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019ead9f-28b3-782c-bb64-93a202d2bc65" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_Security12bTitle"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_Security12bTitle_019ead9f-28b3-782c-bb64-93a202d2bc65" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019ead9f-28b3-7612-88e6-47be437f31b5" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_TradingSymbol"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_TradingSymbol_019ead9f-28b3-7612-88e6-47be437f31b5" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019ead9f-28b3-7f45-95de-b439c0bee93e" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SecurityExchangeName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_SecurityExchangeName_019ead9f-28b3-7f45-95de-b439c0bee93e" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019ead9f-28b3-7ff5-a079-809ef976b774" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019ead9f-28b3-7170-9302-853ca9f98876" xlink:to="loc_dei_EntityTaxIdentificationNumber_019ead9f-28b3-7ff5-a079-809ef976b774" xlink:type="arc" order="22"/>
  </link:definitionLink>
</link:linkbase>
