Sergeant First Class Caldwell was a member of Headquarters Company, 3rd Battalion, 8th Cavalry Regiment, 1st Cavalry Division. He was Killed in Action while fighting the enemy along the Nammyon River near Unsan, North Korea on 2 November 1950.

His remains were recovered on 16 July 1993 and identified on 16 December 2010. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Caldwell was awarded the Purple Heart, the Combat Infantryman 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.