Private DePappa was a Heavy Weapons Infantryman with Heavy Mortar Company, 35th Infantry Regiment, 25th Infantry Division. He was Killed in Action while fighting around the Komam-ni west of Masau, South Korea, on 18 August 1950.

For his leadership and valor, Private DePappa was awarded the Silver Star Medal, 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 and the Republic of Korea War Service Medal.