 In 1837 and 1838, Lamar served in the Georgia House of Representatives.He was elected in 1842 to represent Georgia in the United States House of Representatives during the 28th Congress; however, his service was brief as he resigned and left office on July 29, 1843, after taking office only months before on March 4, 1843.After his resignation in 1843, Lamar returned to his agricultural pursuits.