Senior chief petty officer

Senior Chief Petty Officer is the eighth enlisted rank of the UNSC Navy and is a non-commissioned officer. It is equal in rank to Master Sergeant and First Sergeant in the UNSC Marine Corps and UNSC Army, and Senior Master Sergeant in the UNSC Air Force. It is directly above Chief Petty Officer and directly below Master Chief Petty Officer.

In informal settings, Senior Chief Petty Officers are typically called "Senior" or "senior chief" or just "chief" along with other grades of Chief Petty Officers.