diff --git a/dom/base/Document.cpp b/dom/base/Document.cpp
index 153f55b48caf..5974bc4ad345 100644
--- a/dom/base/Document.cpp
+++ b/dom/base/Document.cpp
@@ -13596,7 +13596,7 @@ static bool HasFullscreenSubDocument(Document& aDoc) {
 // Returns nullptr if a request for Fullscreen API is currently enabled
 // in the given document. Returns a static string indicates the reason
 // why it is not enabled otherwise.
-static const char* GetFullscreenError(Document* aDoc, CallerType aCallerType) {
+const char* Document::GetFullscreenError(CallerType aCallerType) {
   if (!StaticPrefs::full_screen_api_enabled()) {
     return "FullscreenDeniedDisabled";
   }
@@ -13607,13 +13607,18 @@ static const char* GetFullscreenError(Document* aDoc, CallerType aCallerType) {
     return nullptr;
   }
 
-  if (!aDoc->IsVisible()) {
+  if (!IsVisible()) {
     return "FullscreenDeniedHidden";
   }
 
+  if (!FeaturePolicyUtils::IsFeatureAllowed(this,
+                                            NS_LITERAL_STRING("fullscreen"))) {
+    return "FullscreenDeniedFeaturePolicy";
+  }
+
   // Ensure that all containing elements are <iframe> and have allowfullscreen
   // attribute set.
-  BrowsingContext* bc = aDoc->GetBrowsingContext();
+  BrowsingContext* bc = GetBrowsingContext();
   if (!bc || !bc->FullscreenAllowed()) {
     return "FullscreenDeniedContainerNotAllowed";
   }
@@ -13645,7 +13650,7 @@ bool Document::FullscreenElementReadyCheck(FullscreenRequest& aRequest) {
     aRequest.Reject("FullscreenDeniedLostWindow");
     return false;
   }
-  if (const char* msg = GetFullscreenError(this, aRequest.mCallerType)) {
+  if (const char* msg = GetFullscreenError(aRequest.mCallerType)) {
     aRequest.Reject(msg);
     return false;
   }
@@ -13938,10 +13943,6 @@ bool Document::ApplyFullscreen(UniquePtr<FullscreenRequest> aRequest) {
   return true;
 }
 
-bool Document::FullscreenEnabled(CallerType aCallerType) {
-  return !GetFullscreenError(this, aCallerType);
-}
-
 void Document::ClearOrientationPendingPromise() {
   mOrientationPendingPromise = nullptr;
 }
diff --git a/dom/base/Document.h b/dom/base/Document.h
index d9cdbcf902cc..3c2b10905a14 100644
--- a/dom/base/Document.h
+++ b/dom/base/Document.h
@@ -3331,7 +3331,11 @@ class Document : public nsINode,
   void MozSetImageElement(const nsAString& aImageElementId, Element* aElement);
   nsIURI* GetDocumentURIObject() const;
   // Not const because all the fullscreen goop is not const
-  bool FullscreenEnabled(CallerType aCallerType);
+  const char* GetFullscreenError(CallerType);
+  bool FullscreenEnabled(CallerType aCallerType) {
+    return !GetFullscreenError(aCallerType);
+  }
+
   Element* GetTopLayerTop();
   // Return the fullscreen element in the top layer
   Element* GetUnretargetedFullScreenElement();
diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
index 5db9903e9381..f2a452e24a60 100644
--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -3100,10 +3100,8 @@ static const char* GetFullscreenError(CallerType aCallerType,
     return nullptr;
   }
 
-  // Ensure feature policy allows using the fullscreen API
-  if (!FeaturePolicyUtils::IsFeatureAllowed(aDocument,
-                                            NS_LITERAL_STRING("fullscreen"))) {
-    return "FullscreenDeniedFeaturePolicy";
+  if (const char* error = aDocument->GetFullscreenError(aCallerType)) {
+    return error;
   }
 
   // Bypass user interaction checks if preference is set
diff --git a/dom/html/test/file_fullscreen-featurePolicy-inner.html b/dom/html/test/file_fullscreen-featurePolicy-inner.html
index 2e290008297f..844684b05456 100644
--- a/dom/html/test/file_fullscreen-featurePolicy-inner.html
+++ b/dom/html/test/file_fullscreen-featurePolicy-inner.html
@@ -6,22 +6,24 @@
 <body onload="doRequestFullscreen()">
 <script>
 function doRequestFullscreen() {
+  let isChrome = location.search.includes("chrome");
+
   function handler(evt) {
     document.removeEventListener("fullscreenchange", handler);
     document.removeEventListener("fullscreenerror", handler);
+    const enabled = isChrome ? SpecialPowers.wrap(document).fullscreenEnabled
+                             : document.fullscreenEnabled;
     if (evt.type == "fullscreenchange") {
-      document.addEventListener("fullscreenchange", () => parent.continueTest(evt.type), {once: true});
+      document.addEventListener("fullscreenchange", () => parent.continueTest(evt.type, enabled), {once: true});
       document.exitFullscreen();
     } else {
-      parent.continueTest(evt.type);
+      parent.continueTest(evt.type, enabled);
     }
   }
-  parent.ok(document.fullscreenEnabled, "Fullscreen " +
-            `should be enabled in ${parent.testTargetName}`);
   document.addEventListener("fullscreenchange", handler);
   document.addEventListener("fullscreenerror", handler);
   parent.opener.info("Requesting fullscreen");
-  if (location.search.includes("chrome")) {
+  if (isChrome) {
     SpecialPowers.wrap(document.documentElement).requestFullscreen();
   } else {
     document.documentElement.requestFullscreen();
diff --git a/dom/html/test/file_fullscreen-featurePolicy.html b/dom/html/test/file_fullscreen-featurePolicy.html
index 8646a6e03dd4..27ba632f1b47 100644
--- a/dom/html/test/file_fullscreen-featurePolicy.html
+++ b/dom/html/test/file_fullscreen-featurePolicy.html
@@ -61,23 +61,25 @@ async function nextTest() {
     const setupForInnerTest = targetName => {
       window.testTargetName = targetName;
       return new Promise(resolve => {
-        window.continueTest = e => {
+        window.continueTest = (event, enabled) => {
           delete window.testTargetName;
           delete window.continueTest;
-          resolve(e);
+          resolve({ event, enabled });
         };
         document.body.appendChild(iframe);
       });
     };
 
-    const event = await setupForInnerTest(
+    const { event, enabled } = await setupForInnerTest(
       `an iframe+allowfullscreen+allow:${value}+isChrome:${isChrome}`
     );
 
     if (isChrome) {
       is(event, "fullscreenchange", "Expected a fullscreenchange event");
+      ok(enabled, "Should be enabled in chrome");
     } else {
       is(event, expectedEvent, "Expected a " + expectedEvent + " event");
+      is(enabled, expectedEvent == "fullscreenchange", "Should be appropriately enabled");
     }
     iframe.remove();
   }
diff --git a/testing/web-platform/tests/feature-policy/feature-policy-header-policy-disallowed-for-all.https.sub.html b/testing/web-platform/tests/feature-policy/feature-policy-header-policy-disallowed-for-all.https.sub.html
index 9a0f483ce44b..971af0fa070d 100644
--- a/testing/web-platform/tests/feature-policy/feature-policy-header-policy-disallowed-for-all.https.sub.html
+++ b/testing/web-platform/tests/feature-policy/feature-policy-header-policy-disallowed-for-all.https.sub.html
@@ -17,6 +17,7 @@
     assert_array_equals(
       document.featurePolicy.getAllowlistForFeature('fullscreen'),
       []);
+    assert_false(document.fullscreenEnabled, "fullscreenEnabled should reflect feature policy properly");
   }, header_policy + ' -- test allowlist is []');
 
   // Test that fullscreen is disallowed on all subframes.
