Turning to politics, Joseph was elected to the United States Congress in 1810 taking his seat on March 4, 1811 and served several years until March 3, 1815. Though a Federalist, opposing War with Great Britain, he voted with the Republican party in declaring War. He was a Presidential Elector in 1816, casting his vote for James Monroe (1758–1831). He later broke with the Federalist party and by the time of the next election he was a Democratic-Republican, in which he was elected to another term in the House of Representatives from March 4, 1819 until he resigned on January 6, 1826. In his second tenure in Congress, Kent continued as chairman of the Committee on the District of Columbia.