During the Korean War, Second Lieutenant Mack was a pilot of a F-80 "Shooting Star" jet fighter, flying 23 missions over Korea. He was critically injured in an accident, when his aircraft crashed on Luzon Island in the Philippines on 2 January 1953 and evacuated to the United States. He died at the Veterans Hospital at Canandaigua, New York, on 10 September 1953.

Mack was awarded the Air Medal with 2 Oak Leaf Clusters, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.