Wickham then served as operations officer of the 1st Battle Group, 5th Cavalry, in Korea, and later commanded in combat the 5th Battalion, 7th Cavalry Regiment, 1st Cavalry Division in Vietnam, where he was seriously wounded.
Wickham then served as operations officer of the 1st Battle Group, 5th Cavalry, in Korea, and was executive officer to Army Chief of Staff Harold Johnson. Later he commanded in combat the 5th Battalion, 7th Cavalry Regiment, 1st Cavalry Division in Vietnam, where he was seriously wounded.