diff --git a/action.yml b/action.yml
index 46de1c9..3a26b67 100644
--- a/action.yml
+++ b/action.yml
@@ -28,6 +28,9 @@ inputs:
   repository_level:
     description: "Set to true to enable repository level registration token"
     default: "false"
+  custom_script:
+    description: "Custom user script to run (as root) before starting the runner"
+    default: ""
 runs:
   using: "composite"
   steps:
@@ -91,6 +94,17 @@ runs:
             --token ${{ steps.get-registration.outputs.registration_token }} --name $(hostname) --work /home/ghrunner \
             --labels ${{ steps.get-registration.outputs.runner_scope }} --ephemeral
 
+          # Running custom script if provided
+          if [[ -n "${{ inputs.custom_script }}" ]]; then
+            CUSTOM_SCRIPT=$(mktemp $HOME/custom_script.XXXXXX.sh)
+            cat > $CUSTOM_SCRIPT <<'CUSTOM_SCRIPT_EOF'
+            ${{ inputs.custom_script }}
+            CUSTOM_SCRIPT_EOF
+            chmod 0700 $CUSTOM_SCRIPT
+            echo "Running custom user script"
+            sudo $CUSTOM_SCRIPT
+          fi
+
           # Install and start the runner service
           ./svc.sh install
           ./svc.sh start