diff --git a/src/google/adk/sessions/_session_util.py b/src/google/adk/sessions/_session_util.py
index 2cc65949..68340c8b 100644
--- a/src/google/adk/sessions/_session_util.py
+++ b/src/google/adk/sessions/_session_util.py
@@ -16,23 +16,16 @@ from __future__ import annotations
 
 from typing import Any
 from typing import Optional
+from typing import Type
+from typing import TypeVar
 
-from google.genai import types
+M = TypeVar("M")
 
 
-def decode_content(
-    content: Optional[dict[str, Any]],
-) -> Optional[types.Content]:
-  """Decodes a content object from a JSON dictionary."""
-  if not content:
+def decode_model(
+    data: Optional[dict[str, Any]], model_cls: Type[M]
+) -> Optional[M]:
+  """Decodes a pydantic model object from a JSON dictionary."""
+  if data is None:
     return None
-  return types.Content.model_validate(content)
-
-
-def decode_grounding_metadata(
-    grounding_metadata: Optional[dict[str, Any]],
-) -> Optional[types.GroundingMetadata]:
-  """Decodes a grounding metadata object from a JSON dictionary."""
-  if not grounding_metadata:
-    return None
-  return types.GroundingMetadata.model_validate(grounding_metadata)
+  return model_cls.model_validate(data)
diff --git a/src/google/adk/sessions/database_session_service.py b/src/google/adk/sessions/database_session_service.py
index 9eca2753..04af695b 100644
--- a/src/google/adk/sessions/database_session_service.py
+++ b/src/google/adk/sessions/database_session_service.py
@@ -23,6 +23,7 @@ from typing import Any
 from typing import Optional
 import uuid
 
+from google.genai import types
 from sqlalchemy import Boolean
 from sqlalchemy import delete
 from sqlalchemy import Dialect
@@ -252,6 +253,12 @@ class StorageEvent(Base):
   custom_metadata: Mapped[dict[str, Any]] = mapped_column(
       DynamicJSON, nullable=True
   )
+  usage_metadata: Mapped[dict[str, Any]] = mapped_column(
+      DynamicJSON, nullable=True
+  )
+  citation_metadata: Mapped[dict[str, Any]] = mapped_column(
+      DynamicJSON, nullable=True
+  )
 
   partial: Mapped[bool] = mapped_column(Boolean, nullable=True)
   turn_complete: Mapped[bool] = mapped_column(Boolean, nullable=True)
@@ -318,6 +325,14 @@ class StorageEvent(Base):
       )
     if event.custom_metadata:
       storage_event.custom_metadata = event.custom_metadata
+    if event.usage_metadata:
+      storage_event.usage_metadata = event.usage_metadata.model_dump(
+          exclude_none=True, mode="json"
+      )
+    if event.citation_metadata:
+      storage_event.citation_metadata = event.citation_metadata.model_dump(
+          exclude_none=True, mode="json"
+      )
     return storage_event
 
   def to_event(self) -> Event:
@@ -328,17 +343,23 @@ class StorageEvent(Base):
         branch=self.branch,
         actions=self.actions,
         timestamp=self.timestamp.timestamp(),
-        content=_session_util.decode_content(self.content),
         long_running_tool_ids=self.long_running_tool_ids,
         partial=self.partial,
         turn_complete=self.turn_complete,
         error_code=self.error_code,
         error_message=self.error_message,
         interrupted=self.interrupted,
-        grounding_metadata=_session_util.decode_grounding_metadata(
-            self.grounding_metadata
-        ),
         custom_metadata=self.custom_metadata,
+        content=_session_util.decode_model(self.content, types.Content),
+        grounding_metadata=_session_util.decode_model(
+            self.grounding_metadata, types.GroundingMetadata
+        ),
+        usage_metadata=_session_util.decode_model(
+            self.usage_metadata, types.GenerateContentResponseUsageMetadata
+        ),
+        citation_metadata=_session_util.decode_model(
+            self.citation_metadata, types.CitationMetadata
+        ),
     )
 
 
diff --git a/src/google/adk/sessions/vertex_ai_session_service.py b/src/google/adk/sessions/vertex_ai_session_service.py
index 72ff0d6c..6901f4cb 100644
--- a/src/google/adk/sessions/vertex_ai_session_service.py
+++ b/src/google/adk/sessions/vertex_ai_session_service.py
@@ -376,8 +376,9 @@ def _from_api_event(api_event_obj: vertexai.types.SessionEvent) -> Event:
     interrupted = getattr(event_metadata, 'interrupted', None)
     branch = getattr(event_metadata, 'branch', None)
     custom_metadata = getattr(event_metadata, 'custom_metadata', None)
-    grounding_metadata = _session_util.decode_grounding_metadata(
-        getattr(event_metadata, 'grounding_metadata', None)
+    grounding_metadata = _session_util.decode_model(
+        getattr(event_metadata, 'grounding_metadata', None),
+        types.GroundingMetadata,
     )
   else:
     long_running_tool_ids = None
@@ -393,8 +394,8 @@ def _from_api_event(api_event_obj: vertexai.types.SessionEvent) -> Event:
       invocation_id=api_event_obj.invocation_id,
       author=api_event_obj.author,
       actions=event_actions,
-      content=_session_util.decode_content(
-          getattr(api_event_obj, 'content', None)
+      content=_session_util.decode_model(
+          getattr(api_event_obj, 'content', None), types.Content
       ),
       timestamp=api_event_obj.timestamp.timestamp(),
       error_code=getattr(api_event_obj, 'error_code', None),
diff --git a/tests/unittests/sessions/test_session_service.py b/tests/unittests/sessions/test_session_service.py
index 0c005d68..0dd4162e 100644
--- a/tests/unittests/sessions/test_session_service.py
+++ b/tests/unittests/sessions/test_session_service.py
@@ -390,6 +390,11 @@ async def test_append_event_complete(service_type):
       error_code='error_code',
       error_message='error_message',
       interrupted=True,
+      usage_metadata=types.GenerateContentResponseUsageMetadata(
+          prompt_token_count=1, candidates_token_count=1, total_token_count=2
+      ),
+      citation_metadata=types.CitationMetadata(),
+      custom_metadata={'custom_key': 'custom_value'},
   )
   await session_service.append_event(session=session, event=event)