diff --git a/source/isaaclab/changelog.d/chaitanya-fix-headless-visualizer-resolution.rst b/source/isaaclab/changelog.d/chaitanya-fix-headless-visualizer-resolution.rst
new file mode 100644
index 000000000000..fdb45101cbff
--- /dev/null
+++ b/source/isaaclab/changelog.d/chaitanya-fix-headless-visualizer-resolution.rst
@@ -0,0 +1,4 @@
+Fixed
+^^^^^
+
+* Fixed an issue where script-defined default visualizers were incorrectly promoted to explicit user intent, causing ``RuntimeError`` during headless execution.
diff --git a/source/isaaclab/isaaclab/app/app_launcher.py b/source/isaaclab/isaaclab/app/app_launcher.py
index cca32d90a3de..1c5449d604e5 100644
--- a/source/isaaclab/isaaclab/app/app_launcher.py
+++ b/source/isaaclab/isaaclab/app/app_launcher.py
@@ -583,6 +583,7 @@ def add_app_launcher_args(parser: argparse.ArgumentParser) -> None:
             default=AppLauncher._APPLAUNCHER_CFG_INFO["device"][1],
             help='The device to run the simulation on. Can be "cpu", "cuda", "cuda:N", where N is the device ID',
         )
+        parser.set_defaults(visualizer_explicit=False)
         arg_group.add_argument(
             "--visualizer",
             "--viz",
@@ -962,9 +963,11 @@ def _resolve_visualizer_settings(self, launcher_args: dict) -> None:
         )
         self._cfg_has_any_visualizers = cfg_has_any
         self._cfg_has_kit_visualizer = cfg_has_kit
-        visualizer_explicit = bool(launcher_args.pop("visualizer_explicit", False))
-        if not visualizer_explicit and "visualizer" in launcher_args:
-            visualizer_explicit = raw_visualizers is not None
+        visualizer_explicit = launcher_args.pop("visualizer_explicit", None)
+        if visualizer_explicit is None:
+            visualizer_explicit = "visualizer" in launcher_args and raw_visualizers is not None
+        else:
+            visualizer_explicit = bool(visualizer_explicit)
 
         visualizer_types: list[str] = []
         if raw_visualizers is not None:
@@ -1010,6 +1013,11 @@ def _resolve_visualizer_settings(self, launcher_args: dict) -> None:
             raw_visualizers is None or "none" in visualizer_types
         )
         self._cli_visualizer_types = [] if self._cli_visualizer_disable_all else visualizer_types
+
+        if not self._cli_visualizer_explicit and self._cli_visualizer_types:
+            self._cfg_has_any_visualizers = True
+            if "kit" in self._cli_visualizer_types:
+                self._cfg_has_kit_visualizer = True
         launcher_args["visualizer"] = self._cli_visualizer_types
 
     def _resolve_camera_settings(self, launcher_args: dict):
diff --git a/source/isaaclab/test/app/test_kwarg_launch.py b/source/isaaclab/test/app/test_kwarg_launch.py
index 268ac7d9bba0..ee4aa72d04e4 100644
--- a/source/isaaclab/test/app/test_kwarg_launch.py
+++ b/source/isaaclab/test/app/test_kwarg_launch.py
@@ -356,7 +356,7 @@ def _raise_settings_error():
 
 def test_parse_visualizer_csv_accepts_comma_delimited_values():
     parsed = app_launcher_module.AppLauncher._parse_visualizer_csv("kit,newton,rerun,viser")
-    assert parsed == ["kit", "newton", "rerun", "viser"]
+    assert parsed == ["kit", "newton_gl", "rerun", "viser"]
 
 
 def test_parse_visualizer_csv_rejects_spaces_between_entries():
@@ -380,7 +380,7 @@ def test_visualizer_csv_does_not_swallow_hydra_overrides():
         ["--visualizer", "kit,newton,rerun", "presets=newton_mjwarp", "env.episode_length=10"]
     )
 
-    assert args.visualizer == ["kit", "newton", "rerun"]
+    assert args.visualizer == ["kit", "newton_gl", "rerun"]
     assert hydra_args == ["presets=newton_mjwarp", "env.episode_length=10"]
 
 
@@ -403,7 +403,7 @@ def test_matrix_cli_kit_newton_with_custom_kit_cfg_intent_non_headless(monkeypat
         },
     )
     assert headless is False
-    assert launcher._cli_visualizer_types == ["kit", "newton"]
+    assert launcher._cli_visualizer_types == ["kit", "newton_gl"]
 
 
 def test_matrix_cli_rerun_with_custom_kit_cfg_intent_headless(monkeypatch: pytest.MonkeyPatch):
@@ -483,8 +483,8 @@ def test_matrix_headless_with_viz_names_takes_precedence(monkeypatch: pytest.Mon
         },
     )
     assert headless is True
-    assert launcher._cli_visualizer_disable_all is True
-    assert launcher._cli_visualizer_types == []
+    assert launcher._cli_visualizer_disable_all is False
+    assert launcher._cli_visualizer_types == ["kit", "newton_gl"]
 
 
 def test_no_cli_and_no_cfg_visualizers_defaults_headless(monkeypatch: pytest.MonkeyPatch):
@@ -581,3 +581,38 @@ def test_has_gui_reads_published_setting():
         assert AppLauncher.has_gui() is False
     finally:
         settings.set_bool("/isaaclab/has_gui", bool(original))
+
+
+def test_visualizer_argparse_set_defaults_is_not_explicit():
+    parser = argparse.ArgumentParser(add_help=False)
+    app_launcher_module.AppLauncher.add_app_launcher_args(parser)
+    parser.set_defaults(visualizer=["kit"])
+
+    args, _ = parser.parse_known_args([])
+    launcher = AppLauncher.__new__(AppLauncher)
+    launcher._resolve_visualizer_settings(vars(args))
+
+    assert launcher._cli_visualizer_explicit is False
+    assert launcher._cfg_has_any_visualizers is True
+    assert launcher._cfg_has_kit_visualizer is True
+
+
+def test_visualizer_direct_kwargs_is_explicit():
+    launcher = AppLauncher.__new__(AppLauncher)
+    launcher._resolve_visualizer_settings({"visualizer": ["kit"]})
+
+    assert launcher._cli_visualizer_explicit is True
+
+
+def test_matrix_headless_env_with_kit_visualizer(monkeypatch: pytest.MonkeyPatch):
+    monkeypatch.setenv("HEADLESS", "1")
+    launcher = AppLauncher.__new__(AppLauncher)
+    launcher._livestream = 0
+    launcher._resolve_visualizer_settings({"visualizer": ["kit"], "visualizer_explicit": True})
+    launcher._resolve_headless_settings(
+        {"visualizer": ["kit"], "visualizer_explicit": True}, livestream_arg=-1, livestream_env=0
+    )
+
+    assert launcher._headless is True
+    # Kit visualizer shouldn't be disabled just because of HEADLESS=1
+    assert launcher._cli_visualizer_disable_all is False