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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019df902-9686-7909-b72d-d33b912f7adb,g:b8ff4778-0b9f-4119-9a2f-8cc1556a6303-->
<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.financeofamerica.com/role/DocumentandEntityInformationDocument" xlink:type="simple" xlink:href="foa-20260505.xsd#DocumentandEntityInformationDocument"/>
  <link:definitionLink xlink:role="http://www.financeofamerica.com/role/DocumentandEntityInformationDocument" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_019df902-9686-7584-8d78-61ce071f15ac" 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_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_DocumentInformationTable_019df902-9686-7584-8d78-61ce071f15ac" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityListingsExchangeAxis_019df902-9686-74cd-8864-e692e01b2a2b" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityListingsExchangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_019df902-9686-7584-8d78-61ce071f15ac" xlink:to="loc_dei_EntityListingsExchangeAxis_019df902-9686-74cd-8864-e692e01b2a2b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_019df902-9686-74cd-8864-e692e01b2a2b_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_EntityListingsExchangeAxis_019df902-9686-74cd-8864-e692e01b2a2b" xlink:to="loc_dei_ExchangeDomain_019df902-9686-74cd-8864-e692e01b2a2b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_019df902-9686-7e9a-8ee5-26fcf2ddb1f4" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_ExchangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_EntityListingsExchangeAxis_019df902-9686-74cd-8864-e692e01b2a2b" xlink:to="loc_dei_ExchangeDomain_019df902-9686-7e9a-8ee5-26fcf2ddb1f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_exch_XNYS_019df902-9686-7b25-8381-752cde5e9a39" xlink:href="https://xbrl.sec.gov/exch/2026/exch-2026.xsd#exch_XNYS"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_ExchangeDomain_019df902-9686-7e9a-8ee5-26fcf2ddb1f4" xlink:to="loc_exch_XNYS_019df902-9686-7b25-8381-752cde5e9a39" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_exch_XCHI_019df902-9686-7b3a-94ee-4505916a256b" xlink:href="https://xbrl.sec.gov/exch/2026/exch-2026.xsd#exch_XCHI"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_ExchangeDomain_019df902-9686-7e9a-8ee5-26fcf2ddb1f4" xlink:to="loc_exch_XCHI_019df902-9686-7b3a-94ee-4505916a256b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019df902-9686-7d21-b65e-1d87a76db355" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_DocumentType_019df902-9686-7d21-b65e-1d87a76db355" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019df902-9686-75c0-b56a-2a4383e15502" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_DocumentPeriodEndDate_019df902-9686-75c0-b56a-2a4383e15502" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019df902-9686-7485-b096-e2907faf30d0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_EntityRegistrantName_019df902-9686-7485-b096-e2907faf30d0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019df902-9686-74a2-ac5e-c4fe1149b667" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019df902-9686-74a2-ac5e-c4fe1149b667" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019df902-9686-7aff-a64a-e3115360e085" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_EntityFileNumber_019df902-9686-7aff-a64a-e3115360e085" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019df902-9686-7898-b4ae-aabf78e6506a" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_EntityTaxIdentificationNumber_019df902-9686-7898-b4ae-aabf78e6506a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019df902-9686-74a3-9db3-98f20ac0f430" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_EntityAddressAddressLine1_019df902-9686-74a3-9db3-98f20ac0f430" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine2_019df902-9686-71d6-b9ba-b63264ebce0c" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressAddressLine2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_EntityAddressAddressLine2_019df902-9686-71d6-b9ba-b63264ebce0c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019df902-9686-77c4-b554-797b6d01d03d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_EntityAddressCityOrTown_019df902-9686-77c4-b554-797b6d01d03d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019df902-9686-7a53-9633-bb17e72f1972" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_EntityAddressStateOrProvince_019df902-9686-7a53-9633-bb17e72f1972" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019df902-9686-7493-a05b-07859af94940" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_EntityAddressPostalZipCode_019df902-9686-7493-a05b-07859af94940" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019df902-9686-7a85-97d5-9fbbf559a603" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_CityAreaCode_019df902-9686-7a85-97d5-9fbbf559a603" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019df902-9686-7c30-8874-c7fbf88044fa" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_LocalPhoneNumber_019df902-9686-7c30-8874-c7fbf88044fa" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_019df902-9686-7f21-a0a8-bc18b69afe9d" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_WrittenCommunications_019df902-9686-7f21-a0a8-bc18b69afe9d" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_019df902-9686-7503-b3c2-766dd6375929" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_SolicitingMaterial_019df902-9686-7503-b3c2-766dd6375929" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_019df902-9686-72a0-9871-be4c0ea78897" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_PreCommencementTenderOffer_019df902-9686-72a0-9871-be4c0ea78897" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_019df902-9686-78a6-9e9b-a4968c1940d0" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_019df902-9686-78a6-9e9b-a4968c1940d0" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_019df902-9686-7998-b286-a0773507d462" 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_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_Security12bTitle_019df902-9686-7998-b286-a0773507d462" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_019df902-9686-7f41-8701-dabf3e7a34a5" 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_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_TradingSymbol_019df902-9686-7f41-8701-dabf3e7a34a5" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_019df902-9686-7c27-83e4-0403f0b40c60" 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_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_SecurityExchangeName_019df902-9686-7c27-83e4-0403f0b40c60" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019df902-9686-778e-bb59-af77725f6490" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_EntityEmergingGrowthCompany_019df902-9686-778e-bb59-af77725f6490" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019df902-9686-723b-ab71-12c713f85e79" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_EntityCentralIndexKey_019df902-9686-723b-ab71-12c713f85e79" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019df902-9686-7590-ac77-32eb193f0d5e" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_019df902-9686-7450-960d-ff94d26ab017" xlink:to="loc_dei_AmendmentFlag_019df902-9686-7590-ac77-32eb193f0d5e" xlink:type="arc" order="22"/>
  </link:definitionLink>
</link:linkbase>
