diff --git a/src/ai/backend/manager/models/gql_models/kernel.py b/src/ai/backend/manager/models/gql_models/kernel.py
index cbb52db685..141ef285ba 100644
--- a/src/ai/backend/manager/models/gql_models/kernel.py
+++ b/src/ai/backend/manager/models/gql_models/kernel.py
@@ -5,6 +5,7 @@
     TYPE_CHECKING,
     Any,
     Self,
+    cast,
 )
 
 import graphene
@@ -14,15 +15,17 @@
 
 from ai.backend.common import msgpack, redis_helper
 from ai.backend.common.types import AgentId, KernelId, SessionId
-from ai.backend.manager.models.base import (
+
+from ..base import (
     batch_multiresult_in_scalar_stream,
     batch_multiresult_in_session,
 )
-
 from ..gql_relay import AsyncNode, Connection
-from ..kernel import KernelRow, KernelStatus
+from ..kernel import KernelRow
 from ..user import UserRole
+from ..utils import get_lastest_timestamp_for_status
 from .image import ImageNode
+from .session import SessionStatus
 
 if TYPE_CHECKING:
     from ..gql import GraphQueryContext
@@ -113,7 +116,12 @@ def from_row(cls, ctx: GraphQueryContext, row: KernelRow) -> Self:
             hide_agents = False
         else:
             hide_agents = ctx.local_config["manager"]["hide-agents"]
-        status_history = row.status_history or {}
+
+        timestamp = get_lastest_timestamp_for_status(
+            cast(list[dict[str, str]], row.status_history), SessionStatus.SCHEDULED
+        )
+        scheduled_at = str(timestamp) if timestamp is not None else None
+
         return KernelNode(
             id=row.id,  # auto-converted to Relay global ID
             row_id=row.id,
@@ -129,7 +137,7 @@ def from_row(cls, ctx: GraphQueryContext, row: KernelRow) -> Self:
             created_at=row.created_at,
             terminated_at=row.terminated_at,
             starts_at=row.starts_at,
-            scheduled_at=status_history.get(KernelStatus.SCHEDULED.name),
+            scheduled_at=scheduled_at,
             occupied_slots=row.occupied_slots.to_json(),
             agent_id=row.agent if not hide_agents else None,
             agent_addr=row.agent_addr if not hide_agents else None,
diff --git a/src/ai/backend/manager/models/gql_models/session.py b/src/ai/backend/manager/models/gql_models/session.py
index 95edc71938..d0a8df13b4 100644
--- a/src/ai/backend/manager/models/gql_models/session.py
+++ b/src/ai/backend/manager/models/gql_models/session.py
@@ -56,7 +56,7 @@
     get_permission_ctx,
 )
 from ..user import UserRole
-from ..utils import execute_with_txn_retry
+from ..utils import execute_with_txn_retry, get_lastest_timestamp_for_status
 from .kernel import KernelConnection, KernelNode
 
 if TYPE_CHECKING:
@@ -174,7 +174,7 @@ class Meta:
     # status_changed = GQLDateTime()  # FIXME: generated attribute
     status_info = graphene.String()
     status_data = graphene.JSONString()
-    status_history = graphene.JSONString()
+    status_history = graphene.JSONString(description="Added in 24.12.0.")
     created_at = GQLDateTime()
     terminated_at = GQLDateTime()
     starts_at = GQLDateTime()
@@ -225,7 +225,11 @@ def from_row(
         permissions: Optional[Iterable[ComputeSessionPermission]] = None,
     ) -> Self:
         status_history = row.status_history or {}
-        raw_scheduled_at = status_history.get(SessionStatus.SCHEDULED.name)
+        timestamp = get_lastest_timestamp_for_status(
+            cast(list[dict[str, str]], status_history), SessionStatus.SCHEDULED
+        )
+        scheduled_at = str(timestamp) if timestamp is not None else None
+
         result = cls(
             # identity
             id=row.id,  # auto-converted to Relay global ID
@@ -251,9 +255,7 @@ def from_row(
             created_at=row.created_at,
             starts_at=row.starts_at,
             terminated_at=row.terminated_at,
-            scheduled_at=datetime.fromisoformat(raw_scheduled_at)
-            if raw_scheduled_at is not None
-            else None,
+            scheduled_at=scheduled_at,
             startup_command=row.startup_command,
             result=row.result.name,
             # resources
diff --git a/src/ai/backend/manager/models/kernel.py b/src/ai/backend/manager/models/kernel.py
index 6acd91c674..3db283f899 100644
--- a/src/ai/backend/manager/models/kernel.py
+++ b/src/ai/backend/manager/models/kernel.py
@@ -880,6 +880,7 @@ class Meta:
     # status
     status = graphene.String()
     status_changed = GQLDateTime()
+    status_history = graphene.JSONString(description="Added in 24.12.0.")
     status_info = graphene.String()
     status_data = graphene.JSONString()
     created_at = GQLDateTime()
@@ -931,6 +932,7 @@ def parse_row(cls, ctx: GraphQueryContext, row: KernelRow) -> Mapping[str, Any]:
             # status
             "status": row.status.name,
             "status_changed": row.status_changed,
+            "status_history": row.status_history,
             "status_info": row.status_info,
             "status_data": row.status_data,
             "created_at": row.created_at,