Montgomery was elected as a Democrat to the Fiftieth and to the three succeeding Congresses (March 4, 1887 – March 3, 1895). He served as chairman of the Committee on Expenditures in the Department of War (Fifty-second and Fifty-third Congresses). He was an unsuccessful candidate for re-election to the Fifty-fourth Congress. He served as member of the Dawes Indian Commission, appointed under an act of Congress to negotiate with the Five Civilized Tribes from 1895 to 1898. He resumed the practice of law at Elizabethtown, Kentucky, where he died December 27, 1910. He was interred in City Cemetery.
