diff --git a/homeassistant/components/zwave_js/api.py b/homeassistant/components/zwave_js/api.py
index c3358b6cde0..4051c1f8f7a 100644
--- a/homeassistant/components/zwave_js/api.py
+++ b/homeassistant/components/zwave_js/api.py
@@ -654,6 +654,7 @@ async def websocket_node_comments(
             QR_PROVISIONING_INFORMATION, "options"
         ): QR_PROVISIONING_INFORMATION_SCHEMA,
         vol.Exclusive(QR_CODE_STRING, "options"): QR_CODE_STRING_SCHEMA,
+        vol.Exclusive(DSK, "options"): str,
     }
 )
 @websocket_api.async_response
@@ -676,6 +677,7 @@ async def websocket_add_node(
         or msg.get(QR_PROVISIONING_INFORMATION)
         or msg.get(QR_CODE_STRING)
     )
+    dsk = msg.get(DSK)
 
     @callback
     def async_cleanup() -> None:
@@ -772,6 +774,7 @@ async def websocket_add_node(
             INCLUSION_STRATEGY_NOT_SMART_START[inclusion_strategy.value],
             force_security=force_security,
             provisioning=provisioning,
+            dsk=dsk,
         )
     except ValueError as err:
         connection.send_error(
diff --git a/tests/components/zwave_js/test_api.py b/tests/components/zwave_js/test_api.py
index be8161ff651..9de99be4c0c 100644
--- a/tests/components/zwave_js/test_api.py
+++ b/tests/components/zwave_js/test_api.py
@@ -780,13 +780,39 @@ async def test_add_node(
     client.async_send_command.reset_mock()
     client.async_send_command.return_value = {"success": True}
 
-    # Test Smart Start QR provisioning information with S2 inclusion strategy fails
+    # Test S2 DSK string string
     await ws_client.send_json(
         {
             ID: 6,
             TYPE: "zwave_js/add_node",
             ENTRY_ID: entry.entry_id,
             INCLUSION_STRATEGY: InclusionStrategy.SECURITY_S2.value,
+            DSK: "test_dsk",
+        }
+    )
+
+    msg = await ws_client.receive_json()
+    assert msg["success"]
+
+    assert len(client.async_send_command.call_args_list) == 1
+    assert client.async_send_command.call_args[0][0] == {
+        "command": "controller.begin_inclusion",
+        "options": {
+            "strategy": InclusionStrategy.SECURITY_S2,
+            "dsk": "test_dsk",
+        },
+    }
+
+    client.async_send_command.reset_mock()
+    client.async_send_command.return_value = {"success": True}
+
+    # Test Smart Start QR provisioning information with S2 inclusion strategy fails
+    await ws_client.send_json(
+        {
+            ID: 7,
+            TYPE: "zwave_js/add_node",
+            ENTRY_ID: entry.entry_id,
+            INCLUSION_STRATEGY: InclusionStrategy.SECURITY_S2.value,
             QR_PROVISIONING_INFORMATION: {
                 VERSION: 1,
                 SECURITY_CLASSES: [0],
@@ -813,7 +839,7 @@ async def test_add_node(
     # Test QR provisioning information with S0 inclusion strategy fails
     await ws_client.send_json(
         {
-            ID: 7,
+            ID: 8,
             TYPE: "zwave_js/add_node",
             ENTRY_ID: entry.entry_id,
             INCLUSION_STRATEGY: InclusionStrategy.SECURITY_S0,
@@ -843,7 +869,7 @@ async def test_add_node(
     # Test ValueError is caught as failure
     await ws_client.send_json(
         {
-            ID: 8,
+            ID: 9,
             TYPE: "zwave_js/add_node",
             ENTRY_ID: entry.entry_id,
             INCLUSION_STRATEGY: InclusionStrategy.DEFAULT.value,
@@ -863,7 +889,7 @@ async def test_add_node(
     ):
         await ws_client.send_json(
             {
-                ID: 9,
+                ID: 10,
                 TYPE: "zwave_js/add_node",
                 ENTRY_ID: entry.entry_id,
             }
@@ -879,7 +905,7 @@ async def test_add_node(
     await hass.async_block_till_done()
 
     await ws_client.send_json(
-        {ID: 10, TYPE: "zwave_js/add_node", ENTRY_ID: entry.entry_id}
+        {ID: 11, TYPE: "zwave_js/add_node", ENTRY_ID: entry.entry_id}
     )
     msg = await ws_client.receive_json()