diff --git a/CHANGELOG.md b/CHANGELOG.md
index f65919e57..0119ff0c3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -232,6 +232,7 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- Slack/Identity: thread agent outbound identity (`chat:write.customize` overrides) through the channel reply delivery path so per-agent username, icon URL, and icon emoji are applied to all Slack replies including media messages. (#27134) Thanks @hou-rong.
 - Agents/Subagents delivery: refactor subagent completion announce dispatch into an explicit queue/direct/fallback state machine, recover outbound channel-plugin resolution in cold/stale plugin-registry states across announce/message/gateway send paths, finalize cleanup bookkeeping when announce flow rejects, and treat Telegram sends without `message_id` as delivery failures (instead of false-success `"unknown"` IDs). (#26867, #25961, #26803, #25069, #26741) Thanks @SmithLabsLLC and @docaohieu2808.
 - Telegram/Webhook: pre-initialize webhook bots, switch webhook processing to callback-mode JSON handling, and preserve full near-limit payload reads under delayed handlers to prevent webhook request hangs and dropped updates. (#26156)
 - Slack/Session threads: prevent oversized parent-session inheritance from silently bricking new thread sessions, surface embedded context-overflow empty-result failures to users, and add configurable `session.parentForkMaxTokens` (default `100000`, `0` disables). (#26912) Thanks @markshields-tl.
diff --git a/src/slack/monitor/message-handler/dispatch.ts b/src/slack/monitor/message-handler/dispatch.ts
index 35db7c2f7..b987585a2 100644
--- a/src/slack/monitor/message-handler/dispatch.ts
+++ b/src/slack/monitor/message-handler/dispatch.ts
@@ -9,6 +9,7 @@ import { createReplyPrefixOptions } from "../../../channels/reply-prefix.js";
 import { createTypingCallbacks } from "../../../channels/typing.js";
 import { resolveStorePath, updateLastRoute } from "../../../config/sessions.js";
 import { danger, logVerbose, shouldLogVerbose } from "../../../globals.js";
+import { resolveAgentOutboundIdentity } from "../../../infra/outbound/identity.js";
 import { removeSlackReaction } from "../../actions.js";
 import { createSlackDraftStream } from "../../draft-stream.js";
 import {
@@ -70,6 +71,16 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
   const cfg = ctx.cfg;
   const runtime = ctx.runtime;
 
+  // Resolve agent identity for Slack chat:write.customize overrides.
+  const outboundIdentity = resolveAgentOutboundIdentity(cfg, route.agentId);
+  const slackIdentity = outboundIdentity
+    ? {
+        username: outboundIdentity.name,
+        iconUrl: outboundIdentity.avatarUrl,
+        iconEmoji: outboundIdentity.emoji,
+      }
+    : undefined;
+
   if (prepared.isDirectMessage) {
     const sessionCfg = cfg.session;
     const storePath = resolveStorePath(sessionCfg?.store, {
@@ -190,6 +201,7 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
       textLimit: ctx.textLimit,
       replyThreadTs,
       replyToMode: ctx.replyToMode,
+      ...(slackIdentity ? { identity: slackIdentity } : {}),
     });
     replyPlan.markSent();
   };
diff --git a/src/slack/monitor/replies.test.ts b/src/slack/monitor/replies.test.ts
new file mode 100644
index 000000000..3d0c3e4fc
--- /dev/null
+++ b/src/slack/monitor/replies.test.ts
@@ -0,0 +1,56 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+const sendMock = vi.fn();
+vi.mock("../send.js", () => ({
+  sendMessageSlack: (...args: unknown[]) => sendMock(...args),
+}));
+
+import { deliverReplies } from "./replies.js";
+
+function baseParams(overrides?: Record<string, unknown>) {
+  return {
+    replies: [{ text: "hello" }],
+    target: "C123",
+    token: "xoxb-test",
+    runtime: { log: () => {}, error: () => {}, exit: () => {} },
+    textLimit: 4000,
+    replyToMode: "off" as const,
+    ...overrides,
+  };
+}
+
+describe("deliverReplies identity passthrough", () => {
+  beforeEach(() => {
+    sendMock.mockReset();
+  });
+  it("passes identity to sendMessageSlack for text replies", async () => {
+    sendMock.mockResolvedValue(undefined);
+    const identity = { username: "Bot", iconEmoji: ":robot:" };
+    await deliverReplies(baseParams({ identity }));
+
+    expect(sendMock).toHaveBeenCalledOnce();
+    expect(sendMock.mock.calls[0][2]).toMatchObject({ identity });
+  });
+
+  it("passes identity to sendMessageSlack for media replies", async () => {
+    sendMock.mockResolvedValue(undefined);
+    const identity = { username: "Bot", iconUrl: "https://example.com/icon.png" };
+    await deliverReplies(
+      baseParams({
+        identity,
+        replies: [{ text: "caption", mediaUrls: ["https://example.com/img.png"] }],
+      }),
+    );
+
+    expect(sendMock).toHaveBeenCalledOnce();
+    expect(sendMock.mock.calls[0][2]).toMatchObject({ identity });
+  });
+
+  it("omits identity key when not provided", async () => {
+    sendMock.mockResolvedValue(undefined);
+    await deliverReplies(baseParams());
+
+    expect(sendMock).toHaveBeenCalledOnce();
+    expect(sendMock.mock.calls[0][2]).not.toHaveProperty("identity");
+  });
+});
diff --git a/src/slack/monitor/replies.ts b/src/slack/monitor/replies.ts
index bc89942d2..4c19ac962 100644
--- a/src/slack/monitor/replies.ts
+++ b/src/slack/monitor/replies.ts
@@ -6,7 +6,7 @@ import type { ReplyPayload } from "../../auto-reply/types.js";
 import type { MarkdownTableMode } from "../../config/types.base.js";
 import type { RuntimeEnv } from "../../runtime.js";
 import { markdownToSlackMrkdwnChunks } from "../format.js";
-import { sendMessageSlack } from "../send.js";
+import { sendMessageSlack, type SlackSendIdentity } from "../send.js";
 
 export async function deliverReplies(params: {
   replies: ReplyPayload[];
@@ -17,6 +17,7 @@ export async function deliverReplies(params: {
   textLimit: number;
   replyThreadTs?: string;
   replyToMode: "off" | "first" | "all";
+  identity?: SlackSendIdentity;
 }) {
   for (const payload of params.replies) {
     // Keep reply tags opt-in: when replyToMode is off, explicit reply tags
@@ -38,6 +39,7 @@ export async function deliverReplies(params: {
         token: params.token,
         threadTs,
         accountId: params.accountId,
+        ...(params.identity ? { identity: params.identity } : {}),
       });
     } else {
       let first = true;
@@ -49,6 +51,7 @@ export async function deliverReplies(params: {
           mediaUrl,
           threadTs,
           accountId: params.accountId,
+          ...(params.identity ? { identity: params.identity } : {}),
         });
       }
     }