diff --git a/docs/api/schemas/latest/patchwork.yaml b/docs/api/schemas/latest/patchwork.yaml
index 6c7564b..35dda80 100644
--- a/docs/api/schemas/latest/patchwork.yaml
+++ b/docs/api/schemas/latest/patchwork.yaml
@@ -1649,6 +1649,12 @@ components:
           type: string
           format: iso8601
           readOnly: true
+        actor:
+          type: object
+          title: The user that caused/created this event
+          readOnly: true
+          allOf:
+            - $ref: '#/components/schemas/UserEmbedded'
         payload:
           type: object
     EventCoverCreated:
diff --git a/docs/api/schemas/patchwork.j2 b/docs/api/schemas/patchwork.j2
index e2c8a8c..0fbc243 100644
--- a/docs/api/schemas/patchwork.j2
+++ b/docs/api/schemas/patchwork.j2
@@ -1679,6 +1679,14 @@ components:
           type: string
           format: iso8601
           readOnly: true
+{% if version >= (1, 2) %}
+        actor:
+          type: object
+          title: The user that caused/created this event
+          readOnly: true
+          allOf:
+            - $ref: '#/components/schemas/UserEmbedded'
+{% endif %}
         payload:
           type: object
     EventCoverCreated:
diff --git a/docs/api/schemas/v1.2/patchwork.yaml b/docs/api/schemas/v1.2/patchwork.yaml
index 7dc9579..c186dc0 100644
--- a/docs/api/schemas/v1.2/patchwork.yaml
+++ b/docs/api/schemas/v1.2/patchwork.yaml
@@ -1649,6 +1649,12 @@ components:
           type: string
           format: iso8601
           readOnly: true
+        actor:
+          type: object
+          title: The user that caused/created this event
+          readOnly: true
+          allOf:
+            - $ref: '#/components/schemas/UserEmbedded'
         payload:
           type: object
     EventCoverCreated:
diff --git a/docs/usage/overview.rst b/docs/usage/overview.rst
index e84e13d..273c792 100644
--- a/docs/usage/overview.rst
+++ b/docs/usage/overview.rst
@@ -228,6 +228,9 @@ properties:
 ``date``
   When this event was created
 
+``actor``
+  The user, if any, that caused/created this event
+
 ``payload``
   Additional information
 
diff --git a/patchwork/api/event.py b/patchwork/api/event.py
index e6d467d..e00ce05 100644
--- a/patchwork/api/event.py
+++ b/patchwork/api/event.py
@@ -23,6 +23,7 @@ from patchwork.models import Event
 class EventSerializer(ModelSerializer):
 
     project = ProjectSerializer(read_only=True)
+    actor = UserSerializer()
     patch = PatchSerializer(read_only=True)
     series = SeriesSerializer(read_only=True)
     cover = CoverLetterSerializer(read_only=True)
@@ -50,7 +51,7 @@ class EventSerializer(ModelSerializer):
         data = super(EventSerializer, self).to_representation(instance)
         payload = OrderedDict()
         kept_fields = self._category_map[instance.category] + [
-            'id', 'category', 'project', 'date']
+            'id', 'category', 'project', 'date', 'actor']
 
         for field in [x for x in data]:
             if field not in kept_fields:
@@ -65,10 +66,13 @@ class EventSerializer(ModelSerializer):
 
     class Meta:
         model = Event
-        fields = ('id', 'category', 'project', 'date', 'patch', 'series',
-                  'cover', 'previous_state', 'current_state',
+        fields = ('id', 'category', 'project', 'date', 'actor', 'patch',
+                  'series', 'cover', 'previous_state', 'current_state',
                   'previous_delegate', 'current_delegate', 'created_check')
         read_only_fields = fields
+        versioned_fields = {
+            '1.2': ('actor', ),
+        }
 
 
 class EventList(ListAPIView):
diff --git a/patchwork/tests/api/test_event.py b/patchwork/tests/api/test_event.py
index bff8f40..456f2f5 100644
--- a/patchwork/tests/api/test_event.py
+++ b/patchwork/tests/api/test_event.py
@@ -35,11 +35,16 @@ class TestEventAPI(utils.APITestCase):
     def assertSerialized(self, event_obj, event_json):
         self.assertEqual(event_obj.id, event_json['id'])
         self.assertEqual(event_obj.category, event_json['category'])
+        if event_obj.actor is None:
+            self.assertIsNone(event_json['actor'])
 
         # nested fields
 
         self.assertEqual(event_obj.project.id,
                          event_json['project']['id'])
+        if event_obj.actor is not None:
+            self.assertEqual(event_obj.actor.id,
+                             event_json['actor']['id'])
 
         # TODO(stephenfin): Check other fields
 
@@ -66,10 +71,12 @@ class TestEventAPI(utils.APITestCase):
         # check-created
         create_check(patch=patch)
         # patch-delegated, patch-state-changed
+        actor = create_maintainer(project=patch.project)
         user = create_maintainer(project=patch.project)
         state = create_state()
         patch.delegate = user
         patch.state = state
+        self.assertTrue(patch.is_editable(actor))
         patch.save()
 
         return Event.objects.all()
@@ -176,3 +183,20 @@ class TestEventAPI(utils.APITestCase):
         self.client.force_authenticate(user=user)
         resp = self.client.post(self.api_url(), {'category': 'patch-created'})
         self.assertEqual(status.HTTP_405_METHOD_NOT_ALLOWED, resp.status_code)
+
+    def test_change_delegate(self):
+        """Ensure changing patch delegate via API produces expected event"""
+        patch = create_patch()
+        delegate = create_maintainer(project=patch.project)
+        actor = create_maintainer(project=patch.project)
+
+        self.client.force_authenticate(user=actor)
+        patch_url = reverse('api-patch-detail', kwargs={'pk': patch.id})
+        resp = self.client.patch(patch_url, {'delegate': delegate.id})
+        self.assertEqual(status.HTTP_200_OK, resp.status_code, resp)
+
+        events = Event.objects.all()
+        delegation_event = events.get(category='patch-delegated')
+        self.assertEqual(actor.id, delegation_event.actor.id)
+        self.assertEqual(None, delegation_event.previous_delegate)
+        self.assertEqual(delegate.id, delegation_event.current_delegate.id)
