In Korea, he was a member of the Company G, 7th Infantry Regiment, 3rd Infantry Division. He was awarded a Silver Star for his actions during the withdrawal from the Hungman Beachhead in 1951 and received a battlefield promotion to captain. As a captain, he was made commander of Company G. Shortly after he served as a senior aide to Major General Williston B. Palmer in command of the 10th Corps. He was killed in the crash of a light Army aircraft near Tong Du Chon (Romanization of Korean 동두천 has changed spelling to Dongducheon), South Korea on January 11, 1952. For his leadership and valor, Casey was awarded the Distinguished Service Cross, the Combat Infantryman Badge, the Korean Service Medal and the United Nations Service Medal.