Born in Natchez, Mississippi, Forman moved with his father to Nashville, Washington County, Illinois, in 1851. He attended the public schools, and Washington Seminary, Richview, Illinois. He studied law. He was admitted to the bar in 1870 and commenced practice in Nashville, Illinois. He served as mayor 1878-1884. He served as delegate to all State and National Democratic Conventions from 1876 to 1896. He served as member of the State senate 1884-1888.
Forman was elected as a Democrat to the Fifty-first, Fifty-second, and Fifty-third Congresses (March 4, 1889-March 3, 1895). He served as chairman of the Committee on Militia (Fifty-third Congress). He moved to East St. Louis, Illinois, in 1895. He was an unsuccessful candidate as a Gold Standard Democrat for election as Governor in 1896. He resumed the practice of his profession. He was appointed by President Cleveland as Commissioner of Internal Revenue and served from 1895 to 1899. He died in Champaign, Illinois, June 10, 1908. He was interred in Masonic Cemetery, Nashville, Illinois.