diff --git a/static/app/types/group.tsx b/static/app/types/group.tsx
index a82ca6f4475cf5..6cd883d9acb942 100644
--- a/static/app/types/group.tsx
+++ b/static/app/types/group.tsx
@@ -700,7 +700,9 @@ interface GroupActivitySetPrivate extends GroupActivityBase {
 }
 
 interface GroupActivitySetByAge extends GroupActivityBase {
-  data: Record<string, any>;
+  data: {
+    age?: number | string;
+  };
   type: GroupActivityType.SET_RESOLVED_BY_AGE;
 }
 
diff --git a/static/app/views/issueDetails/activitySection/groupActivityItem.tsx b/static/app/views/issueDetails/activitySection/groupActivityItem.tsx
index cbc5f6c60b177d..90496ae037bab1 100644
--- a/static/app/views/issueDetails/activitySection/groupActivityItem.tsx
+++ b/static/app/views/issueDetails/activitySection/groupActivityItem.tsx
@@ -22,6 +22,7 @@ import {GroupActivityType, IssueCategory as IssueCategoryEnum} from 'sentry/type
 import type {Organization, Team} from 'sentry/types/organization';
 import type {Project} from 'sentry/types/project';
 import type {User} from 'sentry/types/user';
+import {formatDuration} from 'sentry/utils/duration/formatDuration';
 import {useOrganization} from 'sentry/utils/useOrganization';
 import {isSemverRelease} from 'sentry/utils/versions/isSemverRelease';
 
@@ -287,13 +288,20 @@ export function getGroupActivityItem(
           message: resolvedMessage,
         };
       }
-      case GroupActivityType.SET_RESOLVED_BY_AGE:
+      case GroupActivityType.SET_RESOLVED_BY_AGE: {
+        const duration = formatAutoResolveAge(activity.data.age);
         return {
           title: t('Resolved'),
-          message: tct('by [author] due to inactivity', {
-            author,
-          }),
+          message: duration
+            ? tct('by [author] after [duration] of inactivity', {
+                author,
+                duration,
+              })
+            : tct('by [author] due to inactivity', {
+                author,
+              }),
         };
+      }
       case GroupActivityType.SET_RESOLVED_IN_RELEASE: {
         const hasIntegration =
           'integration_id' in activity.data && activity.data.integration_id;
@@ -786,6 +794,22 @@ export function getGroupActivityItem(
   return renderContent();
 }
 
+function formatAutoResolveAge(age: number | string | undefined) {
+  const resolveAge = Number(age);
+  if (!Number.isFinite(resolveAge) || resolveAge <= 0) {
+    return null;
+  }
+
+  const precision = resolveAge > 23 && resolveAge % 24 === 0 ? 'day' : 'hour';
+  const count = Number(
+    formatDuration({duration: [resolveAge, 'hour'], precision, style: 'count'})
+  );
+
+  return precision === 'day'
+    ? tn('%s day', '%s days', count)
+    : tn('%s hour', '%s hours', count);
+}
+
 function ActivityRelease({project, version}: {project: Project; version: string}) {
   const organization = useOrganization();
   return (
diff --git a/static/app/views/issueDetails/activitySection/index.spec.tsx b/static/app/views/issueDetails/activitySection/index.spec.tsx
index 96e219538c8e9c..3f2ff2e6c68b26 100644
--- a/static/app/views/issueDetails/activitySection/index.spec.tsx
+++ b/static/app/views/issueDetails/activitySection/index.spec.tsx
@@ -346,6 +346,50 @@ describe('ActivitySection', () => {
     expect(screen.getByText('Linked external issue')).toBeInTheDocument();
   });
 
+  it('renders auto-resolved activity age as an inactivity duration', async () => {
+    const autoResolvedGroup = GroupFixture({
+      id: '1347',
+      activity: [
+        {
+          type: GroupActivityType.SET_RESOLVED_BY_AGE,
+          id: 'set-resolved-by-age-1',
+          dateCreated: '2020-01-01T00:00:00',
+          data: {age: 504},
+          user: null,
+        },
+        {
+          type: GroupActivityType.SET_RESOLVED_BY_AGE,
+          id: 'set-resolved-by-age-2',
+          dateCreated: '2020-01-02T00:00:00',
+          data: {age: 11},
+          user: null,
+        },
+        {
+          type: GroupActivityType.SET_RESOLVED_BY_AGE,
+          id: 'set-resolved-by-age-3',
+          dateCreated: '2020-01-03T00:00:00',
+          data: {age: 30},
+          user: null,
+        },
+        {
+          type: GroupActivityType.SET_RESOLVED_BY_AGE,
+          id: 'set-resolved-by-age-4',
+          dateCreated: '2020-01-04T00:00:00',
+          data: {age: '48'},
+          user: null,
+        },
+      ],
+      project,
+    });
+
+    render(<ActivitySection group={autoResolvedGroup} />);
+
+    expect(await screen.findByText(/after 21 days of inactivity/)).toBeInTheDocument();
+    expect(screen.getByText(/after 11 hours of inactivity/)).toBeInTheDocument();
+    expect(screen.getByText(/after 30 hours of inactivity/)).toBeInTheDocument();
+    expect(screen.getByText(/after 2 days of inactivity/)).toBeInTheDocument();
+  });
+
   it('renders note and allows for edit', async () => {
     jest.spyOn(indicators, 'addSuccessMessage');