Staff Sergeant is the sixth enlisted rank of the UNSC Marine Corps and the UNSC Army, and the fifth enlisted rank in the UNSC Air Force. It is a staff non-commissioned officer rank. The rank insignia is represented by three gold "chevrons" over one "rocker" and four white "stripes" for the Air Force.
Staff Sergeants typically command squads of 9 - 11 Marines or Army Infantry, although they may be selected to become "Platoon Sergeants", which aid the platoon commander. Avery Johnson and Nolan Byrne were platoon leaders on Harvest, and were tasked with training a Colonial Militia, with each responsible for a platoon-sized group of men. Although a bit different from the other services, it is the Air Force's first non-commissioned officer rank as well as the first rank to which promotion is on a competitive basis.
- Compared to other services, the rank of SSgt. in the Air Force is relatively low despite being a position given to flight sergeants.
- ↑ Halo 3: ODST Screenshot of the Rookie - Upper left chest plate has clear sign of one chevron and two crossed rifles of a United States Marine Corps Lance Corporal. It is assumed that the UNSC uses the same insignia for its Marines.
- ↑ Contact Harvest, page 47