Private First Class Amidon was a member of Company G, 3rd Battalion, 7th Marines, 1st Marine Division. He was listed as Killed in Action while fighting the enemy in Korea on 27 November 1950. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Amidon was awarded the Purple Heart with Gold Star, the Combat Action Ribbon, 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.