Born in Cincinnati, Ohio, Brown attended the common schools and Greenfield Academy, He was graduated from Miami University, Oxford, Ohio, in 1854. He went south and, while serving as tutor at Baton Rouge, Louisiana, studied law. He was admitted to the bar in 1859 and commenced practice in Chillicothe, Ohio. He served as prosecuting attorney of Ross County in 1859 and 1860. In the first year of the American Civil War, Brown enlisted as a private in Company B, Sixty-third Regiment, Ohio Volunteers, September 2, 1861. He was promptly commissioned as a captain on October 23, 1861. Brown lost his left leg on July 22, 1864 in the Atlanta Campaign. He was promoted through the ranks to colonel June 6, 1865. Brown was mustered out of the volunteers on July 8, 1865. In recognition of Brown's service