A non-commissioned officer (NCO) is a military officer who does not hold a commission. They usually earn their position of authority by promotion through the enlisted ranks, and the NCO corps usually includes many grades of enlisted, corporal, and sergeant. In some countries, warrant officers also carry out the duties of NCOs. Non-commissioned officers may be selected to take the lead in various aspects of the mission based on their unique strengths and weaknesses. They are responsible for fulfilling their individual duties and for ensuring that they accomplish all missions as a team.
NCOs are officially divided into two categories: junior non-commissioned officers, consisting of corporals/sailors first class and master corporals/master sailors; and senior non-commissioned officers, consisting of sergeants and petty officers 2nd class. Tactical NCOs are responsible for training leaders for companies of cadets at the U.S. Military Academy, with duties ranging from teaching and supervising drill and ceremony procedures to military training.
