Android
Wake Google Assistant with the Power Button auf Android
On most Android phones, holding down the power button opens the power menu with options like restart, power off, or emergency call. This default behavior blocks the shortcut for launching Google Assistant, which needs its own gesture assignment to take over that button press.
The setting lives inside the system gesture controls, not inside the Google Assistant app itself. Open Settings ➔ System ➔ Gestures ➔ Press and hold power button. Two options appear here: Power menu and Digital assistant. Selecting Digital assistant switches the half-second long press so it wakes Google Assistant instead of showing the shutdown screen.
After the change, a long press on the power button no longer restarts or shuts down the phone. Use the combination of Power button and Volume up, or the power icon in the notification shade, to reach those options again.
This toggle sits under System because it governs hardware button behavior, separate from the voice trigger settings for the assistant. If the power button still opens the shutdown menu after switching the option, check whether the manufacturer's software uses a different label, since some skins list this control under Advanced features or Buttons instead of Gestures.