Chief Commissaryman Klaus served Aboard the destroyer escort USS Nicholas (DDE-449) in Korean waters. He was Killed in Action while engaged with the enemy on 20 May 1953. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Klaus 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.