Master Sergeant Cahill was a veteran of World War II. In Korea, he was a member of the 9th Infantry Regiment, 2nd Infantry Division. He was Killed in Action while defending Yongsan, South Korea, on 13 August 1950.

For his leadership and valor, Master Sergeant Cahill was awarded the Silver Star Medal, the Bronze Star Medal with Oak Leaf Cluster, 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, the Republic of Korea War Service Medal and the World War II Victory Medal.