Thomas Tredwell was born in Smithtown, Long Island, New York, on February 6, 1743, the son of Timothy Tredwell and Mary Platt. In 1764, Tredwell graduated from Princeton University; he was soon after admitted to the bar, and began the practice of law in Plattsburg, New York. From 1777 to 1783, he served as a representative in the New York State Assembly, and was elected to the New York State Senate from 1786-1789. He was an Anti-federalist in the U.S. House of Representatives for two terms, 1791-1795. He again served as a member of the State Senate from 1803 to 1807 and was surrogate of Clinton County, New York, from 1807 until his death on December 30, 1831.
In 1765, he married Ann Hazard, and they had thirteen children, including prominent fur-trader Nathaniel Hazard Tredwell (1768-1855), and Hannah Phoenix Tredwell (b. 1771), who married Reverend Henry Davis.