Sergeant Major of the Army

The Sergeant Major of the Army (SMA) is a unique non-commissioned rank and position of office in the United States Army. The holder of this rank and position is the most senior enlisted member of the Army unless an army sergeant is serving as the senior enlisted advisor to the Chairman of the Joint Chiefs of Staff, in which case he would be the most senior enlisted man and the SMA will be the second-most senior enlisted member of the army. The SMA is appointed to serve as a spokesman to address the issues of enlisted soldiers to all officers, from warrant officers and lieutenants to the army's highest positions. As such, he is the senior enlisted advisor to the Chief of Staff of the US Army. The exact duties vary depending on the chief of staff, though much of the SMA's time is spent traveling throughout the army, observing training and talking with soldiers and their families.

https://en.wikipedia.org/wiki/Sergeant_Major_of_the_Army http://www.army.mil/leaders/sma/