Private Marks was a member of Company B, 1st Battalion, 5th Infantry Regimental Combat Team. He was Killed in Action while fighting the enemy near Chongpyong, South Korea on 25 April 1951.

Marks 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.