The sergeant major of the Marine Corps (officially abbreviated to SMMC)[2][3] is a billet, as well as a unique enlisted grade of rank, and is designated a special paygrade above E-9.

The position also has a unique non-commissioned grade of rank insignia, in the United States Marine Corps.

[5] The post of Sergeant Major of the Marine Corps was established in 1957 from the order of Assistant Chief of Staff for Personnel at Headquarters Marine Corps, Brigadier General James P. Berkeley, as the senior enlisted advisor to the commandant of the Marine Corps,[5] the first such post in any of the five branches of the United States Armed Forces.

[6] In 1970, the rank insignia of the Sergeant Major of the Marine Corps was authorized (which features three stripes, the Eagle, Globe, and Anchor flanked by two five-point stars in the center, and four rockers) as opposed to the standard Sergeant Major rank insignia (which features three stripes, one five-point star in the center, and four rockers), which was used for the rank from the post's creation in 1957 to 1970.

The commandant of the Marine Corps selects the sergeant major of the Marine Corps and typically serves a four-year term, though his service is at the discretion of the Commandant.