A place of many ramblings about macOS and development. If you find something useful on here, it's probably an accident.

Enable Hey Siri in macOS Sierra to activate Siri just like iOS, without additional software. Works from anywhere at any time.

With macOS Sierra, Siri was introduced to the Mac. By default, Siri can be invoked using fn-space (function + space), however on iOS you can use Hey Siri to activate it from anywhere. This feature can be enabled in macOS using a lesser-known Accessibility feature. This is how to set up Hey Siri in macOS Sierra.

Open Accessibility in System Preferences. You can open this by searching for Accessibility or UniversalAccessPref.prefpane in Spotlight search. Choose Dictation in the sidebar. Dictation is under Interacting. This shows the Dictation preferences, which include a variety of preferences responsible for the Siri & Dictation functionality, and includes features not available in any other system preference pane such as Siri or Sound. Check the Enable the dictation keyword phrase option and enter Hey in the box. Just enter Hey , not Hey Siri . It is unnecessary to check the Play sound when command is recognised option as invoking Siri makes the Siri sound anyway. You will see a new menu bar item, a little microphone ( ) indicating the system is waiting for the keyword phrase ( Hey ) to begin listening. Choose Dictation Commands and add a new command with the plus button. Dictation Commands opens a list of commands which Dictation can invoke, one of which will be your new custom command to launch Siri. Set When I say to Siri and add your keyboard shortcut for Siri. Make sure the keyboard shortcut in the Siri preference pane matches this shortcut — it will have to be changed from fn-space since you can’t use fn in a dictation command keyboard shortcut. Update: Instead of using a keyboard shortcut, you can instead use Open Finder Items… and select Siri.app. Thanks to kleerkoat for suggesting this.