In the United States Marine Corps, First Sergeant (abbreviated 1stSgt) is one level below Sergeant Major and Master Gunnery Sergeant it is equal in grade to Master Sergeant, although the two ranks have different responsibilities.
First Sergeant (abbreviated 1stSgt) is one level below Sergeant Major. This is in the United States Marine Corps. First Sergeant (abbreviated 1stSgt) is one level below Master Gunnery Sergeant. This is in the United States Marine Corps. It is equal in grade one level to Master Sergeant. The two ranks have different responsibilities.