The Nominative Senior Enlisted Leader collar insignia was originally designated the Command Sergeant Major collar insignia. It could be worn only by E-9 NCOs who had been appointed as the senior enlisted advisor to a commanding officer. The reason Command Sergeant Majors (CSMs) were give a special collar insignia rather than wearing a collar device based on their branch insignia is because their position requires them to represent all the enlisted personnel in a command; to wear a branch insignia would create an unnecessary appearance of partiality or favoritism.
The position of Command Sergeant Major was established in 1967, a year after the Army had named the first Sergeant Major of the Army. Just as that position provides enlisted personnel with an opportunity to have their concerns and complaints addressed the highest levels of the Army command structure, the position of Command Sergeant Major has the same duties but at a command level. At smaller commands, E-9 Sergeant Majors may be assigned the job of a Command Sergeant Major; in those cases they would wear the Nominative Senior Enlisted Leader Collar insignia rather than their branch insignia.
Command Sergeant Majors and Sergeant Majors serving in those roles advise their commanders on the training, performance, morale, conduct, appearance, and overall well-being of enlisted Soldiers. They are also tasked with administering their unit’s Noncommissioned Officer’s Development Program. These positions are analogous to the ones created by the Navy’s Command Senior Enlisted Leader (CSEL) program in which CPOs, Senior CPOs, and Master CPOs serve as the senior enlisted advisor to their unit’s commander.