Sergeant McKinney was a member of the Heavy Mortar Company, 32nd Infantry Regiment, 7th Infantry Division. He was listed as Missing in Action while fighting the enemy in North Korea on 2 December 1950. He was presumed dead on 11 March 1954. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

McKinney was awarded the Purple Heart, the Combat Infantryman's Badge, 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.