diff --git a/ghost/admin/app/components/modal-post-history.js b/ghost/admin/app/components/modal-post-history.js
index 489b860a7b..05aba6646e 100644
--- a/ghost/admin/app/components/modal-post-history.js
+++ b/ghost/admin/app/components/modal-post-history.js
@@ -51,7 +51,10 @@ export default class ModalPostHistory extends Component {
                 latest: index === 0,
                 createdAt: revision.get('createdAt'),
                 title: revision.get('title'),
-                custom_excerpt: revision.get('customExcerpt'),
+                // custom_excerpt is a new field that was added to the post-revision model
+                // that may not have been populated for older revisions. To cover that case
+                // we revert to the current post's customExcerpt to avoid losing data when restoring.
+                custom_excerpt: revision.get('customExcerpt') ?? this.post.customExcerpt,
                 feature_image: revision.get('featureImage'),
                 feature_image_alt: revision.get('featureImageAlt'),
                 feature_image_caption: revision.get('featureImageCaption'),
diff --git a/ghost/admin/tests/acceptance/editor/post-revisions-test.js b/ghost/admin/tests/acceptance/editor/post-revisions-test.js
index fc2ce08864..b8606480d4 100644
--- a/ghost/admin/tests/acceptance/editor/post-revisions-test.js
+++ b/ghost/admin/tests/acceptance/editor/post-revisions-test.js
@@ -142,4 +142,52 @@ describe('Acceptance: Post revisions', function () {
         // post has been saved with correct data
         expect(post.attrs.customExcerpt).to.equal('Old excerpt');
     });
+
+    it('reverts to current post excerpt if revision excerpt is missing (with editorExcerpt feature flag)', async function () {
+        enableLabsFlag(this.server, 'editorExcerpt');
+
+        const post = this.server.create('post', {
+            title: 'Current Title',
+            customExcerpt: 'Current excerpt',
+            status: 'draft'
+        });
+        this.server.create('post-revision', {
+            post,
+            title: post.title,
+            postStatus: 'draft',
+            author: post.authors.models[0],
+            createdAt: moment(post.updatedAt).subtract(1, 'hour'),
+            reason: 'explicit_save'
+        });
+        this.server.create('post-revision', {
+            post,
+            title: 'Old Title',
+            customExcerpt: null,
+            postStatus: 'draft',
+            author: post.authors.models[0],
+            createdAt: moment(post.updatedAt).subtract(1, 'day'),
+            reason: 'initial_revision'
+        });
+
+        await visit(`/editor/post/${post.id}`);
+
+        // open post history menu
+        await click('[data-test-psm-trigger]');
+        await click('[data-test-toggle="post-history"]');
+
+        // latest excerpt is set to current
+        expect(find('[data-test-post-history-preview-excerpt]')).to.exist;
+        expect(find('[data-test-post-history-preview-excerpt]')).to.have.trimmed.text('Current excerpt');
+
+        // previous post can be previewed and excerpt is set to current
+        await click('[data-test-revision-item="1"] [data-test-button="preview-revision"]');
+        expect(find('[data-test-post-history-preview-excerpt]')).to.have.trimmed.text('Current excerpt');
+
+        // restore saves current excerpt
+        await click('[data-test-revision-item="1"] [data-test-button="restore-revision"]');
+        await click('[data-test-modal="restore-revision"] [data-test-button="restore"]');
+
+        // post has been saved with correct data
+        expect(post.attrs.customExcerpt).to.equal('Current excerpt');
+    });
 });