Corporal Cahill was a member of the 29th Infantry Regimental Combat Team. He was Killed in Action while fighting the enemy near Hadong, South Korea, on 27 July 1950.

Cahill 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.