US Congressman. He was born one of five children to Jonathan Leet (1768-1853), and his wife Mary Moore Leet (1780-1838) in 1801, but his actual birthdate is unknown. He was educated in preparatory studies and later attended and graduated from the prestigious Washington College (now Washington and Jefferson College), in Washington, Pennsylvania, in 1822. Following his graduation, he studied under Thomas McKean Thompson McKennan (1794-1852), who he would later succeed in the United States Congress, and was admitted to the state bar in 1826 and then commenced his practice of law in his native Washington, Pennsylvania. He then entered politics and served as the Treasurer of Washington County, Pennsylvania, from 1826 to 1830. He also served as Deputy Attorney General of Washington County, Pennsylvania, from 1830 to 1834, as a Member of the Pennsylvania State Senate representing Pennsylvania's 17th District and 20th District from 1834 to 1838. He then decided to run for a seat in the United States Congress and was elected to succeed the outgoing United States Representative Thomas McKean Thompson McKennan (1794-1852), on March 4, 1839. A Member of the Democratic Party, he then served Pennsylvania's 26th District in the United States House of Representatives from March 4, 1839, to March 3, 1831. He was an unsuccessful Candidate for reelection to represent the Twenty-Seventh Congress in 1840. After his term in the United States Congress expired he was succeeded in office by the incoming United States Representative Joseph Lawrence (1786-1842), on March 4, 1841. After his time in the United States Congress, he retired and returned to his practice of law until his death in Washington, Pennsylvania, on June 10, 1844. He was buried in the Cooke Burial Ground in Washington, Pennsylvania. He was married to Margaret Swearinger Cooke Leet (1802-1849), on May 16, 1827, and the couple would have eleven children together.