Sergeant First Class Guide, Meaning , Facts, Information and Description
Sergeant First Class insignia
Sergeant First Class (SFC) is the seventh enlisted rank in the U.S. Army, just above Staff Sergeant and below Master Sergeant, and is a non-commissioned officer.
The position of platoon sergeant is normally kept by a Sergeant First Class and is the primary assistant and advisor to the platoon leader. In abscence of the latter, ranking First Lieutenant or Second Lieutenant, the platoon sergeant becomes acting platoon leader with the same authority as that of the commissioned officer previously in charge of the platoon.