Corporal Lefler was a member of Company G, 2nd Battalion, 38th Infantry Regiment, 2nd Infantry Division. He was seriously wounded by the enemy in South Korea on 6 September 1950 and returned to duty on 26 October 1950. He was listed as Missing in Action while fighting the enemy near Kunu-ri, North Korea on 28 November 1950. He was presumed dead on 15 January 1954. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Lefler was awarded the Purple Heart with Oak Leaf Cluster, 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.