First Lieutenant Humphrey was a member of the 90th Field Artillery Battalion, 25th Infantry Division. He was listed as Missing in Action while fighting the enemy in South Korea on 28 July 1950. He was presumed dead on 31 December 1953.

Humphrey was awarded the Purple Heart, 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.