During Kelly's time as commander, MATS was involved in Operation Deep Freeze, the Cuban Missile Crisis, and the Congo airlift.

In 1928 he entered the United States Military Academy at West Point, New York, and graduated in June 1932 as a second lieutenant in the Infantry.

While under Kelly's command, the group attained the highest record of any B-26 unit in the European theater in number of successful sorties flown, tonnage of bombs dispatched, and enemy aircraft destroyed while at the same time maintaining the highest bombing accuracy score.

This aggressive leadership, together with your efficient administration of the group, was directly responsible for its receiving a unit citation awarded for compiling the outstanding record made by any medium bombardment group during its first year of operations in this theater.General Kelly remained in Europe in command and staff positions until December 1944 when he returned to West Point as director of aviation.

Kelly died on July 8, 1979, at Eglin Air Force Base and was buried in Barrancas National Cemetery in Pensacola, Florida.