diff --git a/app/posts/service.py b/app/posts/service.py
index 77f1357..3539db4 100644
--- a/app/posts/service.py
+++ b/app/posts/service.py
@@ -1,7 +1,7 @@
 import asyncio
 import uuid
 
-from fastapi import HTTPException
+from fastapi import BackgroundTasks, HTTPException
 
 from app.category.enums import Category
 from app.comments.repository import CommentRepository
@@ -27,6 +27,7 @@ class PostService:
     post_like_repository: PostLikeRepository
     comment_repository: CommentRepository
     slack_service: SlackService
+    background_tasks: BackgroundTasks
 
     async def get_post_by_id(self, *, post_id: int, current_user: User) -> PostRead:
         post = await self.post_repository.find_by_id(post_id=post_id)
@@ -170,7 +171,9 @@ async def create_post(
         )
 
         if result.new_univ_major:
-            self.slack_service.notify_new_univ_major(result.new_univ_major)
+            self.background_tasks.add_task(
+                self.slack_service.notify_new_univ_major, result.new_univ_major
+            )
 
         return PostRead.from_post(
             result.post,
@@ -221,7 +224,9 @@ async def update_post(
         )
 
         if result.new_univ_major:
-            self.slack_service.notify_new_univ_major(result.new_univ_major)
+            self.background_tasks.add_task(
+                self.slack_service.notify_new_univ_major, result.new_univ_major
+            )
 
         [like_count, comment_count, is_liked, univ_major] = await asyncio.gather(
             self.post_like_repository.count_by_id(post_id=post_id),
diff --git a/app/slack/service.py b/app/slack/service.py
index aa1ff31..fd4da81 100644
--- a/app/slack/service.py
+++ b/app/slack/service.py
@@ -1,22 +1,15 @@
-from typing import Annotated
-
 import httpx
-from fastapi import BackgroundTasks, Depends
 
 from app.core.config import Environment, core_settings
 from app.utils.dependency import dependency
 
 from .config import slack_settings
 
-BackgroundTasksDep = Annotated[BackgroundTasks, Depends()]
-
 
 @dependency
 class SlackService:
-    background_tasks: BackgroundTasksDep
-
     async def _send_message(self, text: str) -> None:
-        """슬랙으로 메시지를 전송합니다. (내부용)"""
+        """슬랙으로 메시지를 전송합니다."""
         webhook_url = slack_settings.SLACK_WEBHOOK_URL
 
         if not webhook_url:
@@ -37,8 +30,8 @@ async def _send_message(self, text: str) -> None:
             # 슬랙 알림 실패가 메인 로직에 영향 주지 않도록 무시
             pass
 
-    def notify_new_univ_major(self, univ_major: str) -> None:
-        """새로운 학교/전공이 등록되었을 때 슬랙 알림을 백그라운드로 보냅니다."""
+    async def notify_new_univ_major(self, univ_major: str) -> None:
+        """새로운 학교/전공이 등록되었을 때 슬랙 알림을 보냅니다."""
         phase = core_settings.ENVIRONMENT.value.upper()
         message = f"[{phase}] 🎓 새로운 학교/전공 검수 요청: *{univ_major}*"
-        self.background_tasks.add_task(self._send_message, message)
+        await self._send_message(message)