Private Jann was a member of Company K, 3rd Battalion, 7th Cavalry Regiment, 1st Cavalry Division. He was seriously wounded by the enemy in North Korea on 27 September 1951 and returned to duty on 29 September 1951. He was Killed in Action while fighting the enemy in North Korea on 3 October 1951.

Jann was awarded the Purple Heart with Oak Leaf Cluster, 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.