Seaman (E3) Kestner served aboard the destroyer USS Ozborn (DD-846) in Korean waters. His ship was hit by an enemy shore battery near Wosan, North Korea on 24 December 1950, killing him.

Kestner 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.