After enlisting in the Army in 1966, Jack TillyÕs first assignment was to the Republic of Vietnam with A Troop, 1st Squadron, 4th Cavalry Regiment as a vehicle crewman. Upon returning home, he became a Drill Instructor. He has held every key leadership position from tank to First Sergeant, and from 2000 to 2004 he served as the 12th Sergeant Major of the Army. He was the last Vietnam War Veteran to serve in that post, and retired in 2004.