Private First Class Erdman was a member of the 3rd Platoon, Company H, 3rd Battalion, 1st Marines, 1st Marine Division. He was Killed in Action while attacking the Chinese near Hoensong, Korea during "Operation Killer" on 2 March 1951.

Erdman 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.