Moose Yon was born at Ft. Douglas, Utah, on July 6, 1934. He attended Episcopal High School in Alexandria, Virginia, before receiving an appointment to the United States Military Academy in 1956. He earned the Nickname "Moose" through his frequent trips to Canada and his large physique.
Following graduation, Moose completed Airborne and Ranger Schools before being assigned to the 82nd Airborne Division. He served a tour in Europe before returning to Ft Benning as a Staff Officer at the Airborne School and the 11th Air Assault. He volunteered for Special Forces training and served as an A-team leader in Vietnam in 1965.
On his return to the United States, Moose attended the Command and General Staff College at Ft Leavenworth, Kansas, before volunteering for a second tour in Vietnam where he served with the 1st Calvary Division.
Moose returned to other Special Forces assignments in the United States and also served as the Commandant of the Mountain Ranger Camp.