diff --git a/license_manager/apps/api/mixins.py b/license_manager/apps/api/mixins.py
index ad622d24..1aee9356 100644
--- a/license_manager/apps/api/mixins.py
+++ b/license_manager/apps/api/mixins.py
@@ -1,6 +1,9 @@
 from functools import cached_property
 
+from rest_framework.exceptions import ParseError
+
 from license_manager.apps.api import utils
+from license_manager.apps.api_client.lms import LMSApiClient
 
 
 class UserDetailsFromJwtMixin:
@@ -18,9 +21,17 @@ def decoded_jwt(self):
 
         return utils.get_decoded_jwt(self.request)
 
-    @property
+    @cached_property
     def lms_user_id(self):
-        return utils.get_key_from_jwt(self.decoded_jwt, 'user_id')
+        """
+        Retrieve the LMS user ID.
+        """
+        try:
+            return utils.get_key_from_jwt(self.decoded_jwt, 'user_id')
+        except ParseError:
+            lms_client = LMSApiClient()
+            user_id = lms_client.fetch_lms_user_id(self.request.user.email)
+            return user_id
 
     @property
     def user_email(self):
diff --git a/license_manager/apps/api/v1/tests/test_views.py b/license_manager/apps/api/v1/tests/test_views.py
index 9c7efc8a..cd4e3e34 100644
--- a/license_manager/apps/api/v1/tests/test_views.py
+++ b/license_manager/apps/api/v1/tests/test_views.py
@@ -3227,17 +3227,23 @@ def test_get_subsidy_missing_course_key(self):
         assert response.status_code == status.HTTP_400_BAD_REQUEST
 
     @mock.patch('license_manager.apps.api.v1.views.utils.get_decoded_jwt')
-    def test_get_subsidy_no_jwt(self, mock_get_decoded_jwt):
+    @mock.patch('license_manager.apps.api.mixins.LMSApiClient')
+    def test_get_subsidy_no_jwt(self, MockLMSApiClient, mock_get_decoded_jwt):
         """
-        Verify the view returns a 400 if the user_id could not be found in the JWT.
+        Verify the view makes an API call to fetch lmsUserId if user_id could not be found in the JWT.
         """
         self._assign_learner_roles()
         mock_get_decoded_jwt.return_value = {}
         url = self._get_url_with_params()
+
+        # Mock the behavior of LMSApiClient to return a sample user ID
+        mock_lms_client = MockLMSApiClient.return_value
+        mock_lms_client.fetch_lms_user_id.return_value = 443
         response = self.api_client.get(url)
+        assert status.HTTP_404_NOT_FOUND == response.status_code
 
-        assert status.HTTP_400_BAD_REQUEST == response.status_code
-        assert '`user_id` is required and could not be found in your jwt' in str(response.content)
+        # Assert that the LMSApiClient.fetch_lms_user_id method was called once with the correct argument
+        mock_lms_client.fetch_lms_user_id.assert_called_once_with(self.user.email)
 
     def test_get_subsidy_no_subscription_for_enterprise_customer(self):
         """
diff --git a/license_manager/apps/api_client/lms.py b/license_manager/apps/api_client/lms.py
new file mode 100644
index 00000000..21b8eed3
--- /dev/null
+++ b/license_manager/apps/api_client/lms.py
@@ -0,0 +1,43 @@
+import logging
+
+import requests
+from django.conf import settings
+
+from license_manager.apps.api_client.base_oauth import BaseOAuthClient
+
+
+logger = logging.getLogger(__name__)
+
+
+class LMSApiClient(BaseOAuthClient):
+    """
+    API client for calls to the LMS.
+    """
+    api_base_url = settings.LMS_URL
+    user_details_endpoint = api_base_url + '/api/user/v1/accounts'
+
+    def fetch_lms_user_id(self, email):
+        """
+        Fetch user details for the specified user email.
+
+        Arguments:
+            email (str): Email of the user for which we want to fetch details for.
+
+        Returns:
+            str: lms_user_id of the user.
+        """
+        # {base_api_url}/api/user/v1/accounts?email=edx@example.com
+        try:
+            query_params = {'email': email}
+            response = self.client.get(self.user_details_endpoint, params=query_params)
+            response.raise_for_status()
+            response_json = response.json()
+            return response_json[0].get('id')
+        except requests.exceptions.HTTPError as exc:
+            logger.error(
+                'Failed to fetch user details for user {email} because {reason}'.format(
+                    email=email,
+                    reason=str(exc),
+                )
+            )
+            raise exc