diff --git a/lms/services/user.py b/lms/services/user.py
index 6a7dbca286..cbb97b2ef3 100644
--- a/lms/services/user.py
+++ b/lms/services/user.py
@@ -75,6 +75,9 @@ def upsert_user(self, lti_user: LTIUser) -> User:
     def upsert_lms_user(self, user: User, lti_params: LTIParams) -> LMSUser:
         """Upsert LMSUser based on a User object."""
         self._db.flush()  # Make sure User has hit the DB on the current transaction
+
+        # API ID, only Canvas for now
+        lms_api_user_id = lti_params.get("custom_canvas_user_id")
         lms_user = bulk_upsert(
             self._db,
             LMSUser,
@@ -86,6 +89,7 @@ def upsert_lms_user(self, user: User, lti_params: LTIParams) -> LMSUser:
                     "h_userid": user.h_userid,
                     "email": user.email,
                     "display_name": user.display_name,
+                    "lms_api_user_id": lms_api_user_id,
                 }
             ],
             index_elements=["h_userid"],
@@ -100,6 +104,7 @@ def upsert_lms_user(self, user: User, lti_params: LTIParams) -> LMSUser:
                         text('"lms_user"."lti_v13_user_id"'),
                     ),
                 ),
+                "lms_api_user_id",
             ],
         ).one()
         bulk_upsert(
diff --git a/tests/unit/lms/services/user_test.py b/tests/unit/lms/services/user_test.py
index 3813ccd80c..f669d113fd 100644
--- a/tests/unit/lms/services/user_test.py
+++ b/tests/unit/lms/services/user_test.py
@@ -65,6 +65,8 @@ def test_upsert_user_doesnt_save_email_for_existing_students(
 
     def test_upsert_lms_user(self, service, lti_user, pyramid_request, db_session):
         user = service.upsert_user(lti_user)
+        pyramid_request.lti_params["custom_canvas_user_id"] = "lms_api_user_id"
+
         lms_user = service.upsert_lms_user(user, pyramid_request.lti_params)
 
         lms_user = db_session.scalars(
@@ -75,6 +77,7 @@ def test_upsert_lms_user(self, service, lti_user, pyramid_request, db_session):
         assert lms_user.email == user.email
         assert lms_user.updated == user.updated
         assert lms_user.lti_v13_user_id == pyramid_request.lti_params.v13.get("sub")
+        assert lms_user.lms_api_user_id == "lms_api_user_id"
 
     def test_upsert_lms_user_doesnt_clear_lti_v13_user_id(
         self, service, lti_user, pyramid_request, db_session