diff --git a/frontend/src/components/timeline/Timeline.tsx b/frontend/src/components/timeline/Timeline.tsx
index 74169c4..7b09bf3 100644
--- a/frontend/src/components/timeline/Timeline.tsx
+++ b/frontend/src/components/timeline/Timeline.tsx
@@ -220,6 +220,17 @@ export function Timeline() {
   // they share one cache entry, regardless of filter state.
   const { data: photos = [], isLoading } = usePhotosQuery()
 
+  // Auto-focus the first photo on initial grid load so arrow-key nav
+  // works immediately without a pre-click. Only fires when there's no
+  // current active photo — we never clobber the user's selection or
+  // the one they restored by navigating back from preview.
+  useEffect(() => {
+    if (viewMode !== 'grid') return
+    if (activePhotoId) return
+    if (photos.length === 0) return
+    selectPhoto(photos[0].id)
+  }, [viewMode, activePhotoId, photos, selectPhoto])
+
   // Membership in the active heap (for the basket affordance). Subscribed
   // once at this level so we don't have hundreds of thumbnails each
   // subscribing to the same query.