In 1866, Miller moved to
Fort Wayne, Indiana, where he formed a partnership with William H. Coombs. Upon the retirement of
Albert G. Porter from the Indianapolis law firm of Porter, Harrison & Hines, in 1874, Miller was invited to become a member of that firm, which became then the firm of Harrison, Hines & Miller; and was "for many years... a trusted advisor" to leaders of the Republican Party in Indiana. At the time of his appointment, it was reported that Miller was "considered a wealthy man, having grown rich in the practice of his profession". Miller served in that capacity for the duration of Harrison's term, until 1893. As Attorney General, Miller personally handled a number of matters of importance to the administration, including litigation over the status of the
Bering Sea, defense of the constitutionality of the
McKinley Tariff, and of the
Interstate Commerce Act of 1887 and the
International Copyright Act of 1891. He also managed the admission of
North Dakota,
South Dakota,
Montana,
Washington,
Idaho and
Wyoming to the Union. Miller also played a key role in the notorious matter of the death of
David S. Terry, a former California Supreme Court Justice who was shot and killed by a U.S. marshal while attempting to attack U.S. Supreme Court justice
Stephen Johnson Field, who had previously sentenced Terry to six months in jail for contempt of court in connection with a case. Terry had threatened Field, and Miller personally directed the U.S. marshal service to defend Field. When California authorities sought to prosecute the marshal who shot Terry, Miller asserted his authority to protect the safety of the federal judiciary, and personally argued the cause on the Supreme Court, which ruled in his favor. After his retirement from the cabinet, Miller returned to Indianapolis and resumed active practice as a member of the firm of Miller, Winter & Elam, later succeeded by the firm of Miller, Shirley, Miller & Thompson, and later still Miller, Dailey & Thompson. From 1893 to 1898, he also served as a trustee of his alma mater, Hamilton College. ==Personal life and death==