Chief Master Sergeant (CMSgt) is the ninth, and highest, enlisted rank in the United States Air Force, just above Senior Master Sergeant, and is a senior non-commissioned officer. The official term of address is "Chief Master Sergeant" or "Chief".
Attaining the rank of Chief Master Sergeant is the pinnacle of an Air Force enlisted member's career. Some Chief Master Sergeants manage the efforts of all enlisted personnel within their unit or major subsection thereof, while others run major staff functions at higher headquarters levels. All Chief Master Sergeants are expected to serve as mentors for company-grade and field-grade commissioned officers, as well as noncommissioned officers and junior enlisted members, and to serve as advisors to unit commanders and senior officers.
By federal law, only one percent of the Air Force enlisted force may hold the rank of Chief Master Sergeant.
Air Force Junior ROTC
The grade of Cadet Chief Master Sergeant (C/CMSgt) is the ninth enlisted grade of the Air Force Junior ROTC program. Cadet Chief Master Sergeants are to be referred to as "Chief" or "Chief Master Sergeant" by other cadets. At this rank a Chief usually serves as a Squadron, or Group/Wing senior enlisted advisor. If there is no deputy squadron commander, the Chief can be considered the squadron's second in command unless there is another officer in line above the rank of Cadet Major. Just like in the active Air Force, some units only allow a small number of cadets to be promoted to this rank. This is the final rank an enlisted cadet is able to receive before being promoted to an officer.