Sergeant First Class (SFC) is the seventh enlisted rank (E-7) in the U.S. Army, ranking above staff sergeant (E-6) and below master sergeant and first sergeant (E-8), and is the first non-commissioned officer rank designated as a senior non-commissioned officer (SNCO).

A sergeant first class is typically assigned as a platoon sergeant at the company level or battalion operations non-commissioned officer in charge at the battalion level, but may also hold other positions depending on the type of unit. In a combat arms role, a sergeant first class is typically in charge of from 18 soldiers and four tanks in an armor platoon to 40 soldiers in a rifle platoon. A sergeant first class's primary responsibilities are tactical logistics, tactical casualty evacuations, and serving as the senior tactical adviser to the platoon leader. Sergeant first class replaced the rank of technical sergeant in 1948. (However, the U.S. Air Force, which separated from the Army in 1947, retained the rank of technical sergeant and the U.S. Marine Corps had the rank of technical sergeant until 1959.)