Whitman was appointed judge of the superior court in 1818. associate judge of the Hartford County Court 1819-1821, and chief judge 1821-1823. He was one of a committee of three to prepare a revision of the statutes of the Connecticut in 1821. He was a member of the Connecticut Senate in 1822 and elected as an Adams-Clay Republican candidate to the Eighteenth Congress (March 4, 1823 – March 3, 1825). After leaving Congress, he resumed the practice of law and served as a member of the Connecticut House of Representatives in 1831 and 1832. He died in Farmington, Connecticut in 1841.