Livingston was admitted to the bar in 1785, and began to practice law in New York City along with James Kent, Aaron Burr and Alexander Hamilton, rapidly rising to distinction. From 1795 to 1801, Livingston was a Democratic-Republican U.S. Representative in the United States Congress from the state of New York, where he was one of the leaders of the opposition to Jay's Treaty, and introduced the resolution calling upon President George Washington to furnish Congress with the details of the negotiations of the peace treaty with the Kingdom of Great Britain, which the President refused to share. At the close of Washington's administration, he voted with Andrew Jackson and other radicals against the address to the president.