A non-commissioned officer, or NCO, is an enlisted member of the military who holds some degree of authority and who has obtained her promotion from within the non-officer ranks. In the United States, NCOs usually includes the rank of corporal and all grades of sergeant. These officers are considered “the backbone” of the armed forces, and are the primary and most visible leaders in the military. They are also responsible for what is known as operations, or executing the military’s mission, and for training military personnel.

Corporals and Sergeants

The corporal is the base of the NCO ranks, and serves as leader of the smallest units and teams. Corporals are responsible for their soldiers’ individual training, personal appearance and cleanliness. If NCOs are the backbone of the military, corporals are the backbone of the NCO corps—the first line in the officers’ ranks. Sergeants probably have the greatest impact on lower-ranking soldiers like privates, the basic manpower strength of the Army. Sergeants are the private’s first “boss,” and their first and primary leader in their military career. Sergeants are responsible for the individual training, personal appearance and cleanliness of their privates, and must be unquestionably competent to correctly carry out their mission and to care for their assigned soldiers.

Staff Sergeant

The staff sergeant has the same responsibilities as the sergeant, but is somewhat more experienced and must accomplish more duties. Staff sergeants have more influence, oversee more soldiers, and maintain more equipment and property. They also supervise one or more sergeants working under their leadership and are responsible for developing new leaders. Their complexities increase as their responsibilities broaden. If NCOs are the “backbone” of the Army, then staff sergeants are the elements that make up the backbone.

Sergeant First Class

The sergeant first class, better known as the platoon sergeant, is key in the Army’s command structure and is a senior NCO. They usually have several staff sergeants working directly under them, usually as squad leaders. They also assist and advise the platoon leader, and in the platoon leader's absence, will take over command of the platoon. They tend to have 18 or more years of military experience and in conducting military operations.

First Sergeant

The first sergeant is considered the lifeblood of the Army. All unit operations merge here, under his command. They hold formations, instruct platoon sergeants and assist in training all enlisted members. Within this rank includes the master sergeant, who serves as the principal NCO in staff elements at battalion and higher levels.

Sergeant Major

The sergeant major is the highest rank an enlisted soldier can earn. He carries out the policies and standards of the enlisted personnel’s performance, training, appearance and conduct. They also advise and initiate recommendations regarding the local NCO support channel to the commander and staff. They are expected to function without any supervision and can be assigned to any billet in the Army.