He was born to Judge John Wentworth in Somersworth, New Hampshire on July 17, 1745. He graduated from Harvard in 1768 before studying law. He moved to Dover, New Hampshire where he started his practice. His cousin, Governor Wentworth, appointed him the probate register for Strafford County, and he held that post until his death.
He was active in the various revolutionary committees, and was elected to the convention (later the State Assembly) from Dover every year from 1776 to 1780. He was a member of the state council, supporting Meshech Ware, from 1780 to 1784, and was a member of the New Hampshire Committee of Safety. That committee operated as the revolutionary government when the Assembly was not in session.
In 1778 and 1779 he was selected as one of the delegates to the Continental Congress. His term of service gave him the chance to sign the Articles of Confederation when the Congress passed that plan to unify the colonies. As New Hampshire established a more stable government, he was elected to the State's Senate from 1784 to 1786. He died on January 10, 1787 and is buried in the Pine Hill Cemetery at Dover.