In the American Civil War, Smith served as Colonel of the 6th Tennessee Cavalry Regiment in the Union Army from 1861 to 1865; and was brevetedt Brigadier General for his services. He was a delegate to the State constitutional convention in 1865. He was a member of the State house of representatives from 1865 to 1867. He also served in the State senate from 1867 to 1869, and again from 1885 to 1887. He was a surveyor of the port of Memphis, Tennessee from 1871 to 1883.