ドン・カルロス・ビューエル
Fitzhugh was appointed to the United States Military Academy in 1859, but left in September 1861 before finishing to join the Union war effort. He was commissioned as a first lieutenant in the 4th United States Regular Artillery in October 1861, and served as an Aide-de-Camp to major general Don Carlos Buell between 1861 and 1863, including during the April 1862 Shiloh Campaign.