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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:01a0639f-194f-78f0-9045-2f6b772ff7bf,g:21c58471-42c4-4e88-840b-ca491fdefef5-->
<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.mfafinancial.com/role/CoverDocument" xlink:type="simple" xlink:href="mfa-20261104.xsd#CoverDocument"/>
  <link:definitionLink xlink:role="http://www.mfafinancial.com/role/CoverDocument" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationLineItems_01a0639f-194f-752d-bdec-772615d8bf08" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable_01a0639f-194f-7659-8025-439dc0312f9d" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_DocumentInformationTable_01a0639f-194f-7659-8025-439dc0312f9d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_01a0639f-194f-770a-86c1-368dc9364aa9" 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_01a0639f-194f-7659-8025-439dc0312f9d" xlink:to="loc_us-gaap_StatementClassOfStockAxis_01a0639f-194f-770a-86c1-368dc9364aa9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a0639f-194f-770a-86c1-368dc9364aa9_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_01a0639f-194f-770a-86c1-368dc9364aa9" xlink:to="loc_us-gaap_ClassOfStockDomain_01a0639f-194f-770a-86c1-368dc9364aa9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a0639f-194f-792b-b014-e36cf47eec06" 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_01a0639f-194f-770a-86c1-368dc9364aa9" xlink:to="loc_us-gaap_ClassOfStockDomain_01a0639f-194f-792b-b014-e36cf47eec06" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_01a0639f-194f-7fd0-8b4f-5be618c4b68c" 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_01a0639f-194f-792b-b014-e36cf47eec06" xlink:to="loc_us-gaap_CommonStockMember_01a0639f-194f-7fd0-8b4f-5be618c4b68c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_mfa_SeriesBCumulativeRedeemablePreferredStockMember_01a0639f-194f-73c9-8af9-f042c1326d35" xlink:href="mfa-20261104.xsd#mfa_SeriesBCumulativeRedeemablePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a0639f-194f-792b-b014-e36cf47eec06" xlink:to="loc_mfa_SeriesBCumulativeRedeemablePreferredStockMember_01a0639f-194f-73c9-8af9-f042c1326d35" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_mfa_SeriesCFixedToFloatingRateCumulativeRedeemablePreferredStockMember_01a0639f-194f-7833-9d55-f967eed45104" xlink:href="mfa-20261104.xsd#mfa_SeriesCFixedToFloatingRateCumulativeRedeemablePreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a0639f-194f-792b-b014-e36cf47eec06" xlink:to="loc_mfa_SeriesCFixedToFloatingRateCumulativeRedeemablePreferredStockMember_01a0639f-194f-7833-9d55-f967eed45104" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_mfa_A8.875SeniorNotesDue2029Member_01a0639f-194f-7949-9fda-417d6301f232" xlink:href="mfa-20261104.xsd#mfa_A8.875SeniorNotesDue2029Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a0639f-194f-792b-b014-e36cf47eec06" xlink:to="loc_mfa_A8.875SeniorNotesDue2029Member_01a0639f-194f-7949-9fda-417d6301f232" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_mfa_A9.00SeniorNotesDue2029Member_01a0639f-194f-7431-869a-1f673de79aee" xlink:href="mfa-20261104.xsd#mfa_A9.00SeniorNotesDue2029Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a0639f-194f-792b-b014-e36cf47eec06" xlink:to="loc_mfa_A9.00SeniorNotesDue2029Member_01a0639f-194f-7431-869a-1f673de79aee" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_01a0639f-194f-70ba-a165-601eca2242e0" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_DocumentType_01a0639f-194f-70ba-a165-601eca2242e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_01a0639f-194f-707e-a71d-b58798d7533d" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_DocumentPeriodEndDate_01a0639f-194f-707e-a71d-b58798d7533d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_01a0639f-194f-74eb-8f42-4cd33075545b" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_EntityRegistrantName_01a0639f-194f-74eb-8f42-4cd33075545b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_01a0639f-194f-7fe7-9328-18c8590c87ac" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_EntityIncorporationStateCountryCode_01a0639f-194f-7fe7-9328-18c8590c87ac" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_01a0639f-194f-7912-8559-d6370eabcab8" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_EntityFileNumber_01a0639f-194f-7912-8559-d6370eabcab8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_01a0639f-194f-74eb-98f2-5fe99a0d6200" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_EntityTaxIdentificationNumber_01a0639f-194f-74eb-98f2-5fe99a0d6200" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_01a0639f-194f-7b6e-8ade-4a1d30584c96" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_EntityAddressAddressLine1_01a0639f-194f-7b6e-8ade-4a1d30584c96" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_01a0639f-194f-7ebe-b53c-0b961696e731" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_EntityAddressCityOrTown_01a0639f-194f-7ebe-b53c-0b961696e731" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_01a0639f-194f-78cb-9a3f-b79f0ddb9a68" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_EntityAddressStateOrProvince_01a0639f-194f-78cb-9a3f-b79f0ddb9a68" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_01a0639f-194f-7c57-87eb-38225efa71d4" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_EntityAddressPostalZipCode_01a0639f-194f-7c57-87eb-38225efa71d4" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_01a0639f-194f-7a32-afec-534c7290f2a0" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_CityAreaCode_01a0639f-194f-7a32-afec-534c7290f2a0" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_01a0639f-194f-7921-ba90-80ee4b2a74b0" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_LocalPhoneNumber_01a0639f-194f-7921-ba90-80ee4b2a74b0" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_01a0639f-194f-7ab4-92fc-45d164fb2024" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_WrittenCommunications_01a0639f-194f-7ab4-92fc-45d164fb2024" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_01a0639f-194f-794b-b218-f9278dffde83" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_SolicitingMaterial_01a0639f-194f-794b-b218-f9278dffde83" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_01a0639f-194f-778d-a5b8-f8dc09911f94" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_PreCommencementTenderOffer_01a0639f-194f-778d-a5b8-f8dc09911f94" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_01a0639f-194f-77e8-8460-366254f03786" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_01a0639f-194f-77e8-8460-366254f03786" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_01a0639f-194f-78ef-9aac-31cde4053698" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_Security12bTitle_01a0639f-194f-78ef-9aac-31cde4053698" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_01a0639f-194f-72fe-ada5-b11e018bf032" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_TradingSymbol_01a0639f-194f-72fe-ada5-b11e018bf032" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_01a0639f-194f-740a-88fe-6ec493589842" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_SecurityExchangeName_01a0639f-194f-740a-88fe-6ec493589842" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_01a0639f-194f-752f-a609-b96cfa310d74" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_EntityEmergingGrowthCompany_01a0639f-194f-752f-a609-b96cfa310d74" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_01a0639f-194f-7955-a0d9-49042389a95a" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_EntityCentralIndexKey_01a0639f-194f-7955-a0d9-49042389a95a" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_01a0639f-194f-78cc-bf6f-1783dc51442e" 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_01a0639f-194f-752d-bdec-772615d8bf08" xlink:to="loc_dei_AmendmentFlag_01a0639f-194f-78cc-bf6f-1783dc51442e" xlink:type="arc" order="21"/>
  </link:definitionLink>
</link:linkbase>
