Allen graduated from the law school of
University of Michigan at
Ann Arbor in March 1867 and was admitted to the
bar, commenced practice in co-partnership with the Hon. B. M. Cutcheon in
Ypsilanti. He became assistant assessor of internal revenue in 1869 and prosecuting attorney of
Washtenaw County in 1872. He was alderman of Ypsilanti 1872-1874 and was elected to the
Michigan State House of Representatives in 1876 and again in 1878, at which time he was elected speaker pro tempore. He was mayor of Ypsilanti in 1880 and was appointed United States Indian agent for Michigan in August 1882, serving until December 1885. Allen lost his first election for the
United States House of Representatives in 1884. In 1886, Allen was elected as a
Republican from
Michigan's 2nd congressional district for the
Fiftieth and
Fifty-first Congresses, serving from March 4, 1887, to March 3, 1891. He was an unsuccessful candidate for reelection in 1890 to the
Fifty-second Congress. ==Last years==