Rose entered the United States Army Reserves after the 1963 baseball season. He was assigned to Fort Knox for six months of active duty, followed by six years of attendance with a 478th Engineering Battalion USAR unit at Fort Thomas, Kentucky. At Fort Knox, he was a platoon guide and graduated from United States Army Basic Training on January 18, 1964, one week before his marriage to Karolyn Englehardt. Rose remained at Fort Knox to assist his sergeant in training the next platoon and to help another sergeant train the fort's baseball team. Later in his Fort Thomas service, Rose served as a company cook which entailed coming in early for the one weekend/month meeting so that he could leave early enough to participate in Reds home games. Other Reds players in the unit included Johnny Bench, Bobby Tolan, and Darrel Chaney.