diff --git a/x-pack/plugins/observability_solution/investigate_app/public/pages/details/components/investigation_notes/investigation_notes.tsx b/x-pack/plugins/observability_solution/investigate_app/public/pages/details/components/investigation_notes/investigation_notes.tsx
index 7cbc07968f2ec..ec63b09358159 100644
--- a/x-pack/plugins/observability_solution/investigate_app/public/pages/details/components/investigation_notes/investigation_notes.tsx
+++ b/x-pack/plugins/observability_solution/investigate_app/public/pages/details/components/investigation_notes/investigation_notes.tsx
@@ -32,7 +32,7 @@ export function InvestigationNotes({ user }: Props) {
   const theme = useTheme();
   const { investigation, addNote, isAddingNote } = useInvestigation();
   const { data: userProfiles, isLoading: isLoadingUserProfiles } = useFetchUserProfiles({
-    profileIds: new Set(investigation?.notes.map((note) => note.createdBy) ?? []),
+    profileIds: new Set(investigation?.notes.map((note) => note.createdBy)),
   });
 
   const [noteInput, setNoteInput] = useState('');
diff --git a/x-pack/plugins/observability_solution/investigate_app/public/pages/list/components/investigation_list.tsx b/x-pack/plugins/observability_solution/investigate_app/public/pages/list/components/investigation_list.tsx
index d75710f817703..52b0105e1d910 100644
--- a/x-pack/plugins/observability_solution/investigate_app/public/pages/list/components/investigation_list.tsx
+++ b/x-pack/plugins/observability_solution/investigate_app/public/pages/list/components/investigation_list.tsx
@@ -6,6 +6,7 @@
  */
 import {
   Criteria,
+  EuiAvatar,
   EuiBadge,
   EuiBasicTable,
   EuiBasicTableColumn,
@@ -14,6 +15,7 @@ import {
   EuiLink,
   EuiLoadingSpinner,
   EuiText,
+  EuiToolTip,
 } from '@elastic/eui';
 import { i18n } from '@kbn/i18n';
 import { InvestigationResponse } from '@kbn/investigation-shared/src/rest_specs/investigation';
@@ -27,6 +29,7 @@ import { InvestigationListActions } from './investigation_list_actions';
 import { InvestigationStats } from './investigation_stats';
 import { InvestigationsError } from './investigations_error';
 import { SearchBar } from './search_bar/search_bar';
+import { useFetchUserProfiles } from '../../../hooks/use_fetch_user_profiles';
 
 export function InvestigationList() {
   const {
@@ -51,6 +54,10 @@ export function InvestigationList() {
     filter: toFilter(status, tags),
   });
 
+  const { data: userProfiles, isLoading: isUserProfilesLoading } = useFetchUserProfiles({
+    profileIds: new Set(data?.results.map((i) => i.createdBy)),
+  });
+
   const investigations = data?.results ?? [];
   const totalItemCount = data?.total ?? 0;
 
@@ -77,6 +84,27 @@ export function InvestigationList() {
         defaultMessage: 'Created by',
       }),
       truncateText: true,
+      render: (value: InvestigationResponse['createdBy']) => {
+        return isUserProfilesLoading ? (
+          <EuiLoadingSpinner size="m" />
+        ) : (
+          <EuiToolTip
+            position="top"
+            content={
+              userProfiles?.[value]?.user.full_name ?? userProfiles?.[value]?.user.username ?? value
+            }
+          >
+            <EuiAvatar
+              name={
+                userProfiles?.[value]?.user.full_name ??
+                userProfiles?.[value]?.user.username ??
+                value
+              }
+              size="s"
+            />
+          </EuiToolTip>
+        );
+      },
     },
     {
       field: 'tags',
diff --git a/x-pack/plugins/observability_solution/investigate_app/server/services/create_investigation.ts b/x-pack/plugins/observability_solution/investigate_app/server/services/create_investigation.ts
index eb8277d7d6f83..6a7355c0ef875 100644
--- a/x-pack/plugins/observability_solution/investigate_app/server/services/create_investigation.ts
+++ b/x-pack/plugins/observability_solution/investigate_app/server/services/create_investigation.ts
@@ -23,7 +23,7 @@ export async function createInvestigation(
     ...params,
     updatedAt: now,
     createdAt: now,
-    createdBy: user.username,
+    createdBy: user.profile_uid!,
     status: 'triage',
     notes: [],
     items: [],
diff --git a/x-pack/plugins/observability_solution/investigate_app/server/services/create_investigation_item.ts b/x-pack/plugins/observability_solution/investigate_app/server/services/create_investigation_item.ts
index cf77887aab0a3..548912b576618 100644
--- a/x-pack/plugins/observability_solution/investigate_app/server/services/create_investigation_item.ts
+++ b/x-pack/plugins/observability_solution/investigate_app/server/services/create_investigation_item.ts
@@ -23,7 +23,7 @@ export async function createInvestigationItem(
   const now = Date.now();
   const investigationItem = {
     id: v4(),
-    createdBy: user.username,
+    createdBy: user.profile_uid!,
     createdAt: now,
     updatedAt: now,
     ...params,
diff --git a/x-pack/plugins/observability_solution/investigate_app/server/services/delete_investigation_item.ts b/x-pack/plugins/observability_solution/investigate_app/server/services/delete_investigation_item.ts
index d40938804badc..a9856cc0eaa99 100644
--- a/x-pack/plugins/observability_solution/investigate_app/server/services/delete_investigation_item.ts
+++ b/x-pack/plugins/observability_solution/investigate_app/server/services/delete_investigation_item.ts
@@ -19,7 +19,7 @@ export async function deleteInvestigationItem(
     throw new Error('Note not found');
   }
 
-  if (item.createdBy !== user.username) {
+  if (item.createdBy !== user.profile_uid) {
     throw new Error('User does not have permission to delete note');
   }
 
diff --git a/x-pack/plugins/observability_solution/investigate_app/server/services/update_investigation_item.ts b/x-pack/plugins/observability_solution/investigate_app/server/services/update_investigation_item.ts
index 7e7f03bc7f12c..f95950560ca08 100644
--- a/x-pack/plugins/observability_solution/investigate_app/server/services/update_investigation_item.ts
+++ b/x-pack/plugins/observability_solution/investigate_app/server/services/update_investigation_item.ts
@@ -25,7 +25,7 @@ export async function updateInvestigationItem(
     throw new Error('Cannot change item type');
   }
 
-  if (item.createdBy !== user.username) {
+  if (item.createdBy !== user.profile_uid) {
     throw new Error('User does not have permission to update item');
   }