diff --git a/electron/gateway/supervisor.ts b/electron/gateway/supervisor.ts
index 34173575..b1ebf420 100644
--- a/electron/gateway/supervisor.ts
+++ b/electron/gateway/supervisor.ts
@@ -194,11 +194,53 @@ async function getListeningProcessIds(port: number): Promise<string[]> {
   return [...new Set(stdout.trim().split(/\r?\n/).map((value) => value.trim()).filter(Boolean))];
 }
 
+async function stopSystemdGatewayService(): Promise<void> {
+  if (process.platform !== 'linux') return;
+
+  try {
+    const cp = await import('child_process');
+
+    const active = await new Promise<boolean>((resolve) => {
+      cp.exec(
+        'systemctl --user is-active openclaw-gateway',
+        { timeout: 5000 },
+        (err, stdout) => {
+          resolve(!err && stdout.trim() === 'active');
+        },
+      );
+    });
+
+    if (!active) return;
+
+    logger.info('Stopping systemd user service openclaw-gateway to prevent auto-respawn');
+    await new Promise<void>((resolve) => {
+      cp.exec(
+        'systemctl --user stop openclaw-gateway',
+        { timeout: 10000 },
+        (err) => {
+          if (err) {
+            logger.warn(`Failed to stop systemd gateway service: ${err.message}`);
+          } else {
+            logger.info('Successfully stopped systemd gateway service');
+          }
+          resolve();
+        },
+      );
+    });
+
+    await new Promise((resolve) => setTimeout(resolve, 2000));
+  } catch (err) {
+    logger.warn('Error while stopping systemd gateway service:', err);
+  }
+}
+
 async function terminateOrphanedProcessIds(port: number, pids: string[]): Promise<void> {
   logger.info(`Found orphaned process listening on port ${port} (PIDs: ${pids.join(', ')}), attempting to kill...`);
 
   if (process.platform === 'darwin') {
     await unloadLaunchctlGatewayService();
+  } else if (process.platform === 'linux') {
+    await stopSystemdGatewayService();
   }
 
   for (const pid of pids) {
@@ -242,19 +284,27 @@ export async function findExistingGatewayProcess(options: {
   const { port, ownedPid } = options;
 
   try {
-    try {
-      const pids = await getListeningProcessIds(port);
-      if (pids.length > 0 && (!ownedPid || !pids.includes(String(ownedPid)))) {
-        await terminateOrphanedProcessIds(port, pids);
-        if (process.platform === 'win32') {
-          await waitForPortFree(port, 10000);
-        }
-        return null;
+    const pids = await getListeningProcessIds(port).catch(() => [] as string[]);
+
+    if (pids.length > 0 && (!ownedPid || !pids.includes(String(ownedPid)))) {
+      // Something non-owned is listening — probe before killing so we can
+      // adopt an externally-managed gateway (e.g. systemd) instead of
+      // entering a kill-restart loop.
+      const ready = await probeGatewayReady(port, 5000);
+      if (ready) {
+        logger.info(`Adopting existing external gateway on port ${port}`);
+        return { port };
+      }
+
+      // Not a healthy gateway — safe to terminate.
+      await terminateOrphanedProcessIds(port, pids);
+      if (process.platform === 'win32') {
+        await waitForPortFree(port, 10000);
       }
-    } catch (err) {
-      logger.warn('Error checking for existing process on port:', err);
+      return null;
     }
 
+    // Either no process is listening or it's our own — probe as before.
     const ready = await probeGatewayReady(port, 5000);
     return ready ? { port } : null;
   } catch {
diff --git a/tests/unit/gateway-supervisor.test.ts b/tests/unit/gateway-supervisor.test.ts
index e2b9e81d..786da823 100644
--- a/tests/unit/gateway-supervisor.test.ts
+++ b/tests/unit/gateway-supervisor.test.ts
@@ -6,9 +6,11 @@ const originalPlatform = process.platform;
 const {
   mockExec,
   mockCreateServer,
+  mockProbeGatewayReady,
 } = vi.hoisted(() => ({
   mockExec: vi.fn(),
   mockCreateServer: vi.fn(),
+  mockProbeGatewayReady: vi.fn(),
 }));
 
 vi.mock('electron', () => ({
@@ -34,6 +36,10 @@ vi.mock('net', () => ({
   createServer: mockCreateServer,
 }));
 
+vi.mock('@electron/gateway/ws-client', () => ({
+  probeGatewayReady: mockProbeGatewayReady,
+}));
+
 class MockUtilityChild extends EventEmitter {
   pid?: number;
   kill = vi.fn();
@@ -74,6 +80,8 @@ describe('gateway supervisor process cleanup', () => {
         },
       };
     });
+
+    mockProbeGatewayReady.mockResolvedValue(false);
   });
 
   afterEach(() => {
@@ -124,6 +132,9 @@ describe('gateway supervisor process cleanup', () => {
       return {} as never;
     });
 
+    // Probe fails — orphaned process is not a healthy gateway
+    mockProbeGatewayReady.mockResolvedValue(false);
+
     const result = await findExistingGatewayProcess({ port: 18789 });
     expect(result).toBeNull();
 
@@ -134,4 +145,72 @@ describe('gateway supervisor process cleanup', () => {
     );
     expect(mockCreateServer).toHaveBeenCalled();
   });
+
+  it('adopts an external gateway when WebSocket probe succeeds', async () => {
+    setPlatform('linux');
+    const { findExistingGatewayProcess } = await import('@electron/gateway/supervisor');
+
+    mockExec.mockImplementation((cmd: string, _opts: object, cb: (err: Error | null, stdout: string) => void) => {
+      if (cmd.includes('lsof')) {
+        cb(null, '5555\n');
+        return {} as never;
+      }
+      cb(null, '');
+      return {} as never;
+    });
+
+    // Healthy external gateway is running
+    mockProbeGatewayReady.mockResolvedValue(true);
+
+    const result = await findExistingGatewayProcess({ port: 18789 });
+    expect(result).toEqual({ port: 18789 });
+
+    // Should NOT have attempted to kill the process
+    expect(mockExec).not.toHaveBeenCalledWith(
+      expect.stringContaining('SIGTERM'),
+      expect.anything(),
+      expect.anything(),
+    );
+  });
+
+  it('stops systemd service before killing orphan on Linux', { timeout: 15000 }, async () => {
+    vi.useFakeTimers();
+    vi.spyOn(process, 'kill').mockImplementation(() => true);
+    setPlatform('linux');
+    const { findExistingGatewayProcess } = await import('@electron/gateway/supervisor');
+
+    mockExec.mockImplementation((cmd: string, _opts: object, cb: (err: Error | null, stdout: string) => void) => {
+      if (cmd.includes('lsof')) {
+        cb(null, '7777\n');
+        return {} as never;
+      }
+      if (cmd.includes('systemctl --user is-active')) {
+        cb(null, 'active');
+        return {} as never;
+      }
+      cb(null, '');
+      return {} as never;
+    });
+
+    // Probe fails — not a healthy gateway
+    mockProbeGatewayReady.mockResolvedValue(false);
+
+    const resultPromise = findExistingGatewayProcess({ port: 18789 });
+    // Advance past all internal setTimeout delays
+    await vi.advanceTimersByTimeAsync(10000);
+    const result = await resultPromise;
+    expect(result).toBeNull();
+
+    expect(mockExec).toHaveBeenCalledWith(
+      'systemctl --user is-active openclaw-gateway',
+      expect.objectContaining({ timeout: 5000 }),
+      expect.any(Function),
+    );
+    expect(mockExec).toHaveBeenCalledWith(
+      'systemctl --user stop openclaw-gateway',
+      expect.objectContaining({ timeout: 10000 }),
+      expect.any(Function),
+    );
+    vi.useRealTimers();
+  });
 });