Lumpkin entered political life by joining the
Democratic-Republican Party. He was elected as a member of the
Georgia House of Representatives, serving four terms from 1804 to 1812. After that, he ran for Congress in 1814, following the
War of 1812, and was elected as a Representative to the
Fourteenth United States Congress, serving one term from March 4, 1815, to March 3, 1817. He was an unsuccessful candidate for reelection. He received an appointment by the Georgia governor as the State Indian Commissioner, where he ran boundary lines between the state of Georgia and Creek Indian lands as part of the
Treaty of the Creek Agency (1818). Nearly a decade later, Lumpkin returned to Congress, being elected to the
Twentieth,
Twenty-first, and
Twenty-second Congresses and serving from March 4, 1827, until his resignation in 1831 before the convening of the Twenty-second Congress. He ran for the
governorship; he was also an appointed commissioner on the Georgia–Florida boundary line commission. Lumpkin was elected Governor of Georgia in November 1831, for what was then the standard two-year term. In that election he received 27,305 votes and the incumbent governor
George R. Gilmer, also a planter, received 25,863 votes. Lumpkin was reelected as governor in 1833, due in part to the
nullification crisis, and served until 1835. In 1835, Lumpkin was appointed as commissioner under the Cherokee treaty, which transferred virtually all of the remainder of Cherokee lands to the United States in exchange for payments and land in Indian Territory. The Cherokee lands were granted to US citizens by
lottery, and several new counties were organized. As governor, Lumpkin directed the release of two missionaries,
Samuel A. Worcester and Elizur Butler, who had been imprisoned for dwelling in the Cherokee territory and refusing to take an oath of allegiance to Georgia. The case was taken before the Supreme Court in
Worcester v. Georgia and decided in their favor in 1832. Lumpkin was elected to the U.S. Senate to fill the vacancy caused by the resignation of
John P. King and served the remainder of his term from November 22, 1837, to March 3, 1841. While in the Senate, he was chairman of the Committee on Manufactures (Twenty-sixth Congress). He was appointed by the governor as a member of the State Board of Public Works. He died a few years after the end of the Civil War, in Athens in 1870; interment was in
Oconee Hill Cemetery. ==Legacy==