Staff Sergeant (SSG) is E-6 rank in the U.S. Army, just above Sergeant and below Sergeant First Class, and is a non-commissioned officer. Staff Sergeants are generally placed in charge of squads, but can also act as platoon sergeants in the absence of a Sergeant First Class. In support units, Staff Sergeants ordinarily hold headquarters positions due to the amount of slots available for SSG in these units. Staff Sergeants are referred to as "Sergeant" except for in certain training environments and schools. The NATO code is OR-6.
The rank of staff sergeant in the U.S. Army (along with Technical Sergeant (renamed Sergeant First Class in 1948) and Master Sergeant) was created by Congress after the First World War.