diff --git a/migrations/0014_add_challenge_winner_id.sql b/migrations/0014_add_challenge_winner_id.sql
new file mode 100644
index 0000000..19c9547
--- /dev/null
+++ b/migrations/0014_add_challenge_winner_id.sql
@@ -0,0 +1,3 @@
+-- Add winner_id to challenges so wins can be counted directly
+ALTER TABLE challenges ADD COLUMN winner_id INTEGER REFERENCES users(id) ON DELETE SET NULL;
+CREATE INDEX idx_challenges_winner ON challenges(winner_id);
diff --git a/worker/repositories/d1/challenge.d1.ts b/worker/repositories/d1/challenge.d1.ts
index ea40cba..84ecb58 100644
--- a/worker/repositories/d1/challenge.d1.ts
+++ b/worker/repositories/d1/challenge.d1.ts
@@ -107,5 +107,13 @@ export function createD1ChallengeRepository(env: Env): ChallengeRepository {
         .bind(status, id)
         .run();
     },
+
+    async setWinner(id: number, userId: number): Promise<void> {
+      await env.DB.prepare(
+        `UPDATE challenges SET winner_id = ?, updated_at = datetime('now') WHERE id = ?`,
+      )
+        .bind(userId, id)
+        .run();
+    },
   };
 }
diff --git a/worker/repositories/d1/stats.d1.ts b/worker/repositories/d1/stats.d1.ts
index d55329a..8d9321c 100644
--- a/worker/repositories/d1/stats.d1.ts
+++ b/worker/repositories/d1/stats.d1.ts
@@ -11,7 +11,7 @@ export function createD1StatsRepository(env: Env): StatsRepository {
         `SELECT
            COALESCE((SELECT SUM(step_count) FROM step_entries WHERE user_id = ?), 0) as total_steps,
            (SELECT COUNT(*) FROM challenge_participants WHERE user_id = ?) as challenges_joined,
-           (SELECT COUNT(*) FROM user_badges WHERE user_id = ? AND badge_type = 'challenge_winner') as challenges_won,
+           (SELECT COUNT(*) FROM challenges WHERE winner_id = ?) as challenges_won,
            (SELECT COUNT(*) FROM user_badges WHERE user_id = ?) as badges_earned`,
       )
         .bind(userId, userId, userId, userId)
diff --git a/worker/repositories/interfaces/challenge.repository.ts b/worker/repositories/interfaces/challenge.repository.ts
index 1d2bacd..2de3305 100644
--- a/worker/repositories/interfaces/challenge.repository.ts
+++ b/worker/repositories/interfaces/challenge.repository.ts
@@ -51,4 +51,9 @@ export interface ChallengeRepository {
    * Update a challenge status
    */
   updateStatus(id: number, status: Challenge["status"]): Promise<void>;
+
+  /**
+   * Set the winner of a completed challenge
+   */
+  setWinner(id: number, userId: number): Promise<void>;
 }
diff --git a/worker/repositories/memory/challenge.memory.ts b/worker/repositories/memory/challenge.memory.ts
index 3b09b7c..b493d09 100644
--- a/worker/repositories/memory/challenge.memory.ts
+++ b/worker/repositories/memory/challenge.memory.ts
@@ -20,6 +20,7 @@ export function createMemoryChallengeRepository(
         mode: input.mode,
         invite_code: input.inviteCode,
         status: input.status ?? "pending",
+        winner_id: null,
         timezone: input.timezone,
         is_recurring: input.isRecurring ? 1 : 0,
         recurring_interval: input.recurringInterval,
@@ -76,5 +77,12 @@ export function createMemoryChallengeRepository(
       challenge.status = status;
       challenge.updated_at = new Date().toISOString();
     },
+
+    async setWinner(id: number, userId: number): Promise<void> {
+      const challenge = store.challenges.find((c) => c.id === id);
+      if (!challenge) return;
+      challenge.winner_id = userId;
+      challenge.updated_at = new Date().toISOString();
+    },
   };
 }
diff --git a/worker/repositories/memory/stats.memory.ts b/worker/repositories/memory/stats.memory.ts
index 83948c8..d5bc35a 100644
--- a/worker/repositories/memory/stats.memory.ts
+++ b/worker/repositories/memory/stats.memory.ts
@@ -14,8 +14,8 @@ export function createMemoryStatsRepository(store: TestStore): StatsRepository {
       const challengesJoined = store.participants.filter(
         (p) => p.user_id === userId,
       ).length;
-      const challengesWon = store.userBadges.filter(
-        (b) => b.user_id === userId && b.badge_type === "challenge_winner",
+      const challengesWon = store.challenges.filter(
+        (c) => c.winner_id === userId,
       ).length;
       const badgesEarned = store.userBadges.filter(
         (b) => b.user_id === userId,
diff --git a/worker/services/challenge-lifecycle.service.ts b/worker/services/challenge-lifecycle.service.ts
index 7bcce2c..ee7c27e 100644
--- a/worker/services/challenge-lifecycle.service.ts
+++ b/worker/services/challenge-lifecycle.service.ts
@@ -187,6 +187,8 @@ export async function finalizeChallenge(
   }
 
   if (winner) {
+    await deps.challengeRepository.setWinner(challenge.id, winner.user_id);
+
     const badge = await deps.badgeRepository.award(
       winner.user_id,
       "challenge_winner",
diff --git a/worker/test/fixtures/challenge.fixture.ts b/worker/test/fixtures/challenge.fixture.ts
index e488005..c57d56c 100644
--- a/worker/test/fixtures/challenge.fixture.ts
+++ b/worker/test/fixtures/challenge.fixture.ts
@@ -30,6 +30,7 @@ export function createChallenge(overrides: Partial<Challenge> = {}): Challenge {
     mode: overrides.mode ?? "daily_winner",
     invite_code: overrides.invite_code ?? `INVITE${id}`,
     status: overrides.status ?? "pending",
+    winner_id: overrides.winner_id ?? null,
     timezone: overrides.timezone ?? "UTC",
     is_recurring: overrides.is_recurring ?? 0,
     recurring_interval: overrides.recurring_interval ?? null,
diff --git a/worker/test/http/helpers.ts b/worker/test/http/helpers.ts
index 919d804..3e7de32 100644
--- a/worker/test/http/helpers.ts
+++ b/worker/test/http/helpers.ts
@@ -133,8 +133,8 @@ export async function insertChallenge(
 ): Promise<Challenge> {
   const challenge = createChallenge(options);
   await env.DB.prepare(
-    `INSERT INTO challenges (id, title, description, creator_id, start_date, end_date, mode, invite_code, status, timezone, is_recurring, recurring_interval, created_at, updated_at)
-     VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+    `INSERT INTO challenges (id, title, description, creator_id, start_date, end_date, mode, invite_code, status, winner_id, timezone, is_recurring, recurring_interval, created_at, updated_at)
+     VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
   )
     .bind(
       challenge.id,
@@ -146,6 +146,7 @@ export async function insertChallenge(
       challenge.mode,
       challenge.invite_code,
       challenge.status,
+      challenge.winner_id,
       challenge.timezone,
       challenge.is_recurring,
       challenge.recurring_interval,
diff --git a/worker/test/http/profile.http.test.ts b/worker/test/http/profile.http.test.ts
index df6444d..e7368ce 100644
--- a/worker/test/http/profile.http.test.ts
+++ b/worker/test/http/profile.http.test.ts
@@ -32,11 +32,6 @@ describe("HTTP /api/profile", () => {
       challenge_id: challenge.id,
       user_id: user.id,
     });
-    await insertBadge(env, {
-      user_id: user.id,
-      badge_type: "challenge_winner",
-    });
-
     const { res, body } = await requestJson<{
       data: {
         user: { id: number };
diff --git a/worker/test/repositories/stats.d1.test.ts b/worker/test/repositories/stats.d1.test.ts
index 631e2b5..52d315d 100644
--- a/worker/test/repositories/stats.d1.test.ts
+++ b/worker/test/repositories/stats.d1.test.ts
@@ -38,6 +38,7 @@ describe("D1 StatsRepository", () => {
       isRecurring: false,
       recurringInterval: null,
     });
+    await challengeRepo.setWinner(challenge.id, user.id);
 
     const participantRepo = createD1ParticipantRepository(env);
     await participantRepo.join(challenge.id, user.id);
diff --git a/worker/test/usecases/get-profile.test.ts b/worker/test/usecases/get-profile.test.ts
index dc05d1b..d7dfece 100644
--- a/worker/test/usecases/get-profile.test.ts
+++ b/worker/test/usecases/get-profile.test.ts
@@ -5,6 +5,7 @@ import { createMemoryRepos } from "../memory";
 import {
   createUser,
   createUserBadge,
+  createChallenge,
   createStepEntry,
   createParticipant,
   resetAllFixtureCounters,
@@ -26,6 +27,12 @@ describe("getProfile", () => {
       user_id: 1,
       badge_type: "challenge_winner",
     });
+    const challenge = createChallenge({
+      id: 1,
+      creator_id: 1,
+      status: "completed",
+      winner_id: 1,
+    });
     const step = createStepEntry({
       user_id: 1,
       date: "2026-01-02",
@@ -37,6 +44,7 @@ describe("getProfile", () => {
     });
     seedTestStore(store, {
       users: [user],
+      challenges: [challenge],
       userBadges: [badge],
       stepEntries: [step],
       participants: [participant],
diff --git a/worker/types.ts b/worker/types.ts
index d1b3280..e3e043a 100644
--- a/worker/types.ts
+++ b/worker/types.ts
@@ -32,6 +32,7 @@ export interface Challenge {
   mode: "daily_winner" | "cumulative";
   invite_code: string;
   status: "pending" | "active" | "completed";
+  winner_id: number | null;
   timezone: string;
   is_recurring: number;
   recurring_interval: "weekly" | "monthly" | null;