Captain Cooney was a veteran of World War II. In Korea, he was the Commanding Officer of Company G, 3rd Battalion, 7th Marines, 1st Marine Division. He was killed by a sniper while checking to ensure none of his men were left behind during withdrawal from Hill 1425 near Yudam-ni, North Korea on 27 November 1950. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

For his leadership and valor, Captain Cooney was awarded the Silver Star Medal, the Bronze Star Medal, the Purple Heart with Gold Star, the Combat Action Ribbon, the Good Conduct Medal, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the American Defense Service Medal, the American Theatre Campaign Medal, the Asia-Pacific Theatre Campaign Metal, the World War II Victory Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.