diff --git a/wagtail/wagtailcore/models.py b/wagtail/wagtailcore/models.py
index 2268a9e87..35122105a 100644
--- a/wagtail/wagtailcore/models.py
+++ b/wagtail/wagtailcore/models.py
@@ -1140,6 +1140,11 @@ class PageRevision(models.Model):
             # If page goes live clear the approved_go_live_at of all revisions
             page.revisions.update(approved_go_live_at=None)
         page.expired = False  # When a page is published it can't be expired
+
+        # Set first_published_at if the page is being published now
+        if page.live and page.first_published_at is None:
+            page.first_published_at = timezone.now()
+
         page.save()
         self.submitted_for_moderation = False
         page.revisions.update(submitted_for_moderation=False)