The Sergeant Major of the Marine Corps is selected by the Commandant of the Marine Corps to serve as his advisor and as the preeminent and highest ranking enlisted Marine with a protocol equivalency of a three-star general officer.
The Sergeant Major of the Marine Corps typically serves a four-year term, though his service is at the discretion of the Commandant of the Marine Corps.
'Sergeant Major of the Marine Corps' is the full wording of the rank, but the verbal address is Sergeant Major.
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Although not officially considered a Sergeant Major of the Marine Corps, Archibald Sommers was appointed to the grade of Sergeant Major on January 1, 1801. It was a solitary post, similar to the modern billet of Sergeant Major of the Marine Corps.
In 1833, an act of legislation made the rank of sergeant major permanent for the Marine Corps. By 1899, five Marines held the rank of sergeant major. The rank was abolished in 1946 and re-introduced in 1954 as part of the Marine Corps rank structure.
The post of Sergeant Major of the Marine Corps was established in 1957 as the senior enlisted advisor to the Commandant of the Marine Corps. It was the first such post in any of the five branches of the United States Armed Forces. The first official Sergeant Major of the Marine Corps was Sergeant Major Wilbur Bestwick.
In 1970, the distinctive rank insignia of the Sergeant Major of the Marine Corps was authorized. It features the Eagle, Globe and Anchor flanked by two five-point stars, as opposed to the standard Sergeant Major rank insignia, which has a single five-point star in the center.