diff --git a/src/registrar/admin.py b/src/registrar/admin.py
index 0b96b4c48..d3530101d 100644
--- a/src/registrar/admin.py
+++ b/src/registrar/admin.py
@@ -5,6 +5,7 @@ from django import forms
 from django.db.models import Value, CharField, Q
 from django.db.models.functions import Concat, Coalesce
 from django.http import HttpResponseRedirect
+from registrar.models.federal_agency import FederalAgency
 from registrar.utility.admin_helpers import (
     get_action_needed_reason_default_email,
     get_rejection_reason_default_email,
@@ -3192,6 +3193,9 @@ class PortfolioAdmin(ListHeaderAdmin):
             return self.add_fieldsets
         return super().get_fieldsets(request, obj)
 
+    # TODO - I think the solution to this may just be to set this as editable.
+    # Then in the underlying page override, we need a fake readonly display that
+    # is toggled on or off.
     def get_readonly_fields(self, request, obj=None):
         """Set the read-only state on form elements.
         We have 2 conditions that determine which fields are read-only:
@@ -3206,6 +3210,14 @@ class PortfolioAdmin(ListHeaderAdmin):
             # straightforward and the readonly_fields list can control their behavior
             readonly_fields.extend([field.name for field in self.model._meta.fields])
 
+        # Make senior_official readonly for federal organizations
+        if obj and obj.organization_type == obj.OrganizationChoices.FEDERAL:
+            if "senior_official" not in readonly_fields:
+                readonly_fields.append("senior_official")
+        elif "senior_official" in readonly_fields:
+            # Remove senior_official from readonly_fields if org is non-federal
+            readonly_fields.remove("senior_official")
+
         if request.user.has_perm("registrar.full_access_permission"):
             return readonly_fields
 
@@ -3228,7 +3240,7 @@ class PortfolioAdmin(ListHeaderAdmin):
             extra_context["domain_requests"] = obj.get_domain_requests(order_by=["requested_domain__name"])
         return super().change_view(request, object_id, form_url, extra_context)
 
-    def save_model(self, request, obj, form, change):
+    def save_model(self, request, obj: Portfolio, form, change):
 
         if hasattr(obj, "creator") is False:
             # ---- update creator ----
@@ -3243,12 +3255,20 @@ class PortfolioAdmin(ListHeaderAdmin):
         if is_federal and obj.organization_name is None:
             obj.organization_name = obj.federal_agency.agency
 
-        # Remove this line when senior_official is no longer readonly in /admin.
-        if obj.federal_agency:
-            if obj.federal_agency.so_federal_agency.exists():
-                obj.senior_official = obj.federal_agency.so_federal_agency.first()
-            else:
-                obj.senior_official = None
+        # TODO - this should be handled almost entirely in javascript
+        # Handle the federal agency and senior official fields
+        if obj.organization_type == obj.OrganizationChoices.FEDERAL:
+            if obj.federal_agency:
+                if obj.federal_agency.so_federal_agency.exists():
+                    obj.senior_official = obj.federal_agency.so_federal_agency.first()
+                else:
+                    obj.senior_official = None
+        else:
+            if obj.federal_agency and obj.federal_agency.agency != "Non-Federal Agency":
+                if obj.federal_agency.so_federal_agency.first() == obj.senior_official:
+                    obj.senior_official = None
+                obj.federal_agency = FederalAgency.objects.filter(agency="Non-Federal Agency").first()
+
 
         super().save_model(request, obj, form, change)
 
diff --git a/src/registrar/assets/js/get-gov-admin.js b/src/registrar/assets/js/get-gov-admin.js
index fd50fbb0c..a3c8b1410 100644
--- a/src/registrar/assets/js/get-gov-admin.js
+++ b/src/registrar/assets/js/get-gov-admin.js
@@ -927,6 +927,7 @@ document.addEventListener('DOMContentLoaded', function() {
 
     // This is the additional information that exists beneath the SO element.
     var contactList = document.querySelector(".field-senior_official .dja-address-contact-list");
+    const federalAgencyContainer = document.querySelector(".field-federal_agency");
     document.addEventListener('DOMContentLoaded', function() {
 
         let isPortfolioPage = document.getElementById("portfolio_form");
@@ -975,11 +976,13 @@ document.addEventListener('DOMContentLoaded', function() {
             let selectedValue = organizationType.value;
             if (selectedValue === "federal") {
                 hideElement(organizationNameContainer);
+                showElement(federalAgencyContainer);
                 if (federalType) {
                     showElement(federalType);
                 }
             } else {
                 showElement(organizationNameContainer);
+                hideElement(federalAgencyContainer);
                 if (federalType) {
                     hideElement(federalType);
                 }