In 1864, he married Nannie McGuire and moved to Washington, D.C. where he became a successful attorney. He defended John Surratt against allegations that he was involved in Abraham Lincoln's assassination, and later represented Samuel J. Tilden at the Electoral Commission of 1877. In 1874, he endowed the Merrick Medal, a prize given annually to the best debater of the Philodemic Society of Georgetown University. He assisted in the prosecution of the star route scandal from 1882 to 1883.