Witherell was born in
Mansfield in the
Province of Massachusetts Bay. After completing preparatory studies, he served in the
Continental Army from 1775 to 1783 during the
American Revolutionary War. He entered service as a private and rose to the rank of Adjutant in the Eleventh Massachusetts Regiment. He was severely wounded in the
Battle of White Plains in 1776. After the war, Witherell studied medicine and law, and was licensed to practice medicine in 1788. He moved to Hampton in the
Vermont Republic in 1788 and to
Fair Haven in 1789 and continued the practice of his profession. Witherell was a member of the
Vermont House of Representatives from 1798 to 1802. He was associate county judge from 1801 to 1803, judge of Rutland County from 1803 to 1806, and an executive councilor from 1802 to 1806. He was elected as a
Democratic-Republican to the
Tenth Congress, serving from March 4, 1807, until May 1, 1808, when he resigned to accept an appointment by President
Thomas Jefferson as one of the Judges of the
Supreme Court for the
Territory of Michigan. While serving in Congress, he argued in favor of the Act that abolished the slave trade, and voted for the Act, which passed in 1808. During the
War of 1812, he was in command of the troops at
Detroit in the absence of General
William Hull, and was taken prisoner when General Hull surrendered. He lived in Fair Haven, Vermont while on
parole from the British and later was exchanged and returned to his duties in
Detroit in the
Michigan Territory. On April 30, 1821, Governor
Lewis Cass and Judges
John Griffin and James Witherell passed a new act that changed the name of the Catholepistemiad or University of Michigania to the
University of Michigan, and put control in the hands of a board of trustees consisting of twenty members plus the governor. After serving as a Supreme Court justice for nearly twenty years, Witherell resigned in 1828 to accept an appointment by President
John Quincy Adams to become Secretary of the Territory. He held the position until May 1830. Witherell was
Acting Governor of the
Territory of Michigan for the first three months of 1830. ==Family life==