diff --git a/internal/controller/inferenceservice_deployment_test.go b/internal/controller/inferenceservice_deployment_test.go
index c2c35aea..57b87110 100644
--- a/internal/controller/inferenceservice_deployment_test.go
+++ b/internal/controller/inferenceservice_deployment_test.go
@@ -3662,11 +3662,12 @@ var _ = Describe("RuntimeBackend interface", func() {
 			Expect(args).NotTo(ContainElement("--model"))
 			Expect(args).To(ContainElements("--host", "::"))
 			Expect(args).To(ContainElements("--port", "8000"))
-			// --enable-metrics is always set so vLLM pods expose /metrics for
-			// PodMonitor scraping (#409).
-			Expect(args).To(ContainElement("--enable-metrics"))
-			// Six elements: <model> --host :: --port 8000 --enable-metrics.
-			Expect(args).To(HaveLen(6))
+			// vLLM has no --enable-metrics flag; it always exposes /metrics.
+			// Emitting the flag makes vLLM reject the command and the pod never
+			// starts (#1030), so it must never appear.
+			Expect(args).NotTo(ContainElement("--enable-metrics"))
+			// Five elements: <model> --host :: --port 8000.
+			Expect(args).To(HaveLen(5))
 		})
 
 		It("should append extraArgs after typed flags", func() {
diff --git a/internal/controller/runtime_vllm.go b/internal/controller/runtime_vllm.go
index 618cb81c..0b6b0ac5 100644
--- a/internal/controller/runtime_vllm.go
+++ b/internal/controller/runtime_vllm.go
@@ -73,8 +73,11 @@ func (b *VLLMBackend) BuildArgs(isvc *inferencev1alpha1.InferenceService, model
 		// which are appended last so the user flag wins.
 		"--host", "::",
 		"--port", fmt.Sprintf("%d", port),
-		"--enable-metrics",
 	}
+	// NOTE: vLLM has no --enable-metrics flag. Its OpenAI server always exposes
+	// Prometheus metrics at /metrics, so there is nothing to enable; passing the
+	// flag makes vLLM's argument parser reject the whole command and the pod
+	// never starts (#1030). The PodMonitor scrapes /metrics unconditionally.
 
 	var err error