Sergeant Lapp was a member of Weapons Company, 3rd Battalion, 5th Marines, 1st Marine Division. He was seriously wounded while fighting the enemy house to house in Seoul, South Korea and died of those wounds on 26 September 1950.

Lapp was awarded the Purple Heart, the Combat Action Ribbon, 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.