Cave Johnson, 1793–1866, American political leader, b. Robertson co., Tenn. He practiced law in his native state and served (1829–37, 1839–45) in the U.S. House of Representatives. Johnson gave active support to James K. Polk in the presidential campaign of 1844 and served (1845–49) as Postmaster General in Polk's cabinet, introducing postage stamps in the U.S. postal system. He later became (1853) a circuit judge in Tennessee. During the Civil War he opposed secession but afterward supported the Confederacy.