diff --git a/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatRepository.kt b/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatRepository.kt
index 2e7e4517..5a9f4bf3 100644
--- a/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatRepository.kt
+++ b/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatRepository.kt
@@ -44,6 +44,8 @@ class ChatRepository(
                 val entities = data.messages.map { it.toEntity(roomId) }
                 Single.fromCallable {
                     kotlinx.coroutines.runBlocking { chatDao.insertMessages(entities) }
+                    // 오래된 메시지 정리(최신 200개 유지)
+                    kotlinx.coroutines.runBlocking { trimOldMessagesInternal(roomId, 200) }
                     data
                 }.subscribeOn(Schedulers.io())
             }
@@ -60,11 +62,50 @@ class ChatRepository(
                 val entities = data.messages.map { it.toEntity(roomId) }
                 Single.fromCallable {
                     kotlinx.coroutines.runBlocking { chatDao.insertMessages(entities) }
+                    // 오래된 메시지 정리(최신 200개 유지)
+                    kotlinx.coroutines.runBlocking { trimOldMessagesInternal(roomId, 200) }
                     data
                 }.subscribeOn(Schedulers.io())
             }
     }
 
+    /**
+     * 로컬 임시 메시지 저장(SENDING 등)
+     */
+    fun saveLocalMessage(roomId: Long, message: ChatMessage): Completable {
+        return Completable.fromAction {
+            kotlinx.coroutines.runBlocking { chatDao.insertMessage(message.toEntity(roomId)) }
+        }.subscribeOn(Schedulers.io())
+    }
+
+    /**
+     * localId 기반 상태 업데이트(SENDING→SENT/FAILED)
+     */
+    fun updateMessageStatusByLocalId(roomId: Long, localId: String, newStatus: MessageStatus): Completable {
+        return Completable.fromAction {
+            // enum을 문자열로 변환하여 쿼리 파라미터로 전달
+            kotlinx.coroutines.runBlocking { chatDao.updateStatusByLocalId(roomId, localId, newStatus.name) }
+        }.subscribeOn(Schedulers.io())
+    }
+
+    /**
+     * 오래된 메시지 정리(방별 최신 keepLatest개 유지)
+     */
+    fun trimOldMessages(roomId: Long, keepLatest: Int = 200): Completable {
+        return Completable.fromAction {
+            kotlinx.coroutines.runBlocking { trimOldMessagesInternal(roomId, keepLatest) }
+        }.subscribeOn(Schedulers.io())
+    }
+
+    private suspend fun trimOldMessagesInternal(roomId: Long, keepLatest: Int) {
+        if (keepLatest <= 0) return
+        val offset = keepLatest - 1
+        val cutoff = chatDao.getNthLatestCreatedAt(roomId, offset)
+        if (cutoff != null) {
+            chatDao.deleteOldMessages(roomId, cutoff)
+        }
+    }
+
     /**
      * 로그아웃 시 모든 로컬 메시지 삭제
      */
diff --git a/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatRoomActivity.kt b/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatRoomActivity.kt
index 9cfecc90..b03359d7 100644
--- a/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatRoomActivity.kt
+++ b/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/ChatRoomActivity.kt
@@ -270,6 +270,11 @@ class ChatRoomActivity : BaseActivity<ActivityChatRoomBinding>(
             isGrouped = false
         )
         appendMessage(ChatListItem.UserMessage(userMsg))
+        // DB에도 임시 메시지 저장(7.3)
+        compositeDisposable.add(
+            chatRepository.saveLocalMessage(roomId, userMsg)
+                .subscribe({ }, { /* 로컬 저장 실패는 UI 진행에 영향 주지 않음 */ })
+        )
 
         // 2) 타이핑 인디케이터 표시
         chatAdapter.showTypingIndicator()
@@ -301,6 +306,14 @@ class ChatRoomActivity : BaseActivity<ActivityChatRoomBinding>(
             items[index] = ChatListItem.UserMessage(updated)
             chatAdapter.setItems(items)
             autoScrollIfAtBottom()
+
+            // DB에도 상태 업데이트 반영(7.3)
+            updated.localId?.let { lid ->
+                compositeDisposable.add(
+                    chatRepository.updateMessageStatusByLocalId(roomId, lid, newStatus)
+                        .subscribe({ }, { /* 실패 시 무시(다음 동기화 시 정합성 확보) */ })
+                )
+            }
         }
     }
 
@@ -385,6 +398,12 @@ class ChatRoomActivity : BaseActivity<ActivityChatRoomBinding>(
                 // 최신 메시지 위치로
                 scrollToBottom()
                 isLoading = false
+
+                // 7.3: 오래된 메시지 정리(백그라운드)
+                compositeDisposable.add(
+                    chatRepository.trimOldMessages(roomId, keepLatest = 200)
+                        .subscribe({ }, { /* 무시 */ })
+                )
             }, { error ->
                 isLoading = false
                 showToast(error.message ?: "채팅방 데이터를 불러오지 못했습니다.")
@@ -489,6 +508,12 @@ class ChatRoomActivity : BaseActivity<ActivityChatRoomBinding>(
                 }
 
                 isLoading = false
+
+                // 7.3: 오래된 메시지 정리(백그라운드)
+                compositeDisposable.add(
+                    chatRepository.trimOldMessages(roomId, keepLatest = 200)
+                        .subscribe({ }, { /* 무시 */ })
+                )
             }, { error ->
                 isLoading = false
                 showToast(error.message ?: "이전 메시지를 불러오지 못했습니다.")
diff --git a/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/db/ChatMessageDao.kt b/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/db/ChatMessageDao.kt
index 54267951..19d3efbd 100644
--- a/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/db/ChatMessageDao.kt
+++ b/app/src/main/java/kr/co/vividnext/sodalive/chat/talk/room/db/ChatMessageDao.kt
@@ -21,6 +21,14 @@ interface ChatMessageDao {
     @Update
     suspend fun updateMessage(message: ChatMessageEntity)
 
+    // 메시지 상태를 localId 기준으로 업데이트(Converter로 문자열 상태 저장)
+    @Query("UPDATE chat_messages SET status = :status WHERE roomId = :roomId AND localId = :localId")
+    suspend fun updateStatusByLocalId(roomId: Long, localId: String, status: String): Int
+
+    // N번째 최신(createdAt DESC) 항목의 createdAt (OFFSET 사용)
+    @Query("SELECT createdAt FROM chat_messages WHERE roomId = :roomId ORDER BY createdAt DESC LIMIT 1 OFFSET :offset")
+    suspend fun getNthLatestCreatedAt(roomId: Long, offset: Int): Long?
+
     @Query("DELETE FROM chat_messages WHERE roomId = :roomId AND createdAt < :cutoffTime")
     suspend fun deleteOldMessages(roomId: Long, cutoffTime: Long)