During the Civil War, Gurley served as colonel and aide-de-camp on the staff of Gen. John C. Frémont in 1861 when Congress was not in session. In 1863, Gurley was appointed Governor of the Arizona Territory by President Abraham Lincoln, but he died of a sudden attack of appendicitis in Green Township, near Cincinnati, on the eve of his departure to assume his duties.
During the Civil War, Gurley served as a colonel and aide-de-camp to General John C. Frémont in 1861 when Congress was not in session. In 1863, he was appointed Governor of the Arizona Territory by President Abraham Lincoln but died suddenly from appendicitis before his departure for the position.