In 1861, Cabell resigned from the United States Army to take a commission as a major in the Confederate Army. After serving in Virginia, he was transferred to the Trans-Mississippi Department, with a promotion to brigadier general on the staff of General Earl Van Dorn. In the fall of 1862, he was wounded at the battles of Corinth and Hatcher's Bridge in Kansas. In 1864 he was captured in a skirmish near Mine Creek, Kansas, and he remained a prisoner of war until August 28, 1865. After the war, he served as the mayor of Dallas (1874-76, 1877-79, 1883-85).