First Lieutenant Shields was the pilot of a F-84G Thunderjet fighter with the 428th Fighter-Bomber Squadron, 474th Fighter-Bomber Group. On 19 July 1953, while on a combat mission, his aircraft received a direct hit by anti-aircraft fire, crashed and disintegrated. He was listed as Missing in Action and was presumed dead on 13 July 1954. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

For his leadership and valor, First Lieutenant Shields was awarded the Distinguished Service Cross, the Air Medal with 2 Oak Leaf Clusters, the Purple Heart, 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.