The sergeant major is an enlisted sergeant who has been chosen as representative of the interests of a company's other enlisted men, in a role communicating with and serving the company’s captain. There can only be one sergeant major per company. A sergeant major is valued for his expertise as a combatant with firsthand field experience as well as for his perspective as an enlisted soldier. Often a sergeant major will be drawn from a pool of first sergeants, all of whom are deputy leaders of retinues. The sergeant major is therefore to the company what the first sergeant is to the retinue.
Equivalent titles to sergeant major exist when a company has a focus on other types of combat skills than melee. For example, the naval version of the sergeant major is the centenar. The hobelar who represents the enlisted sergeants of the cavalry squadron is called staff corporal, given the cavalry’s penchant for avoiding the sergeant rank and its implications where possible., while an archer’s company might have a
A sergeant major who attends a colonel at the regiment level is called a regimental sergeant major, and the one who attends the captain general is called sergeant major general. Because commissioned officers are equites and will often join the cavalry squadron, all sergeants major at all levels should be understood as the de facto leaders of the infantry on the field.