Private First Class Castor was a member of Company B, 1st Battalion, 32nd Infantry Regiment, 7th Infantry Division. He was Killed in Action while fighting the enemy in North Korea on 30 November 1950. His remains were recovered in June 2004 and identified on 14 January 2009. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Castor 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.