1835, June 17—Resigned from the U.S. Army effective June 30; married Colonel Zachary Taylor’s daughter, Sarah Knox Taylor, who died September 15.
1835-1844—Virtually a recluse for 7 years—time spent, for most part, in study of philosophy and Constitutional Law, then followed a period of travel with an enlivening interest in people and public affairs.
1845, February 26—Married Varina Howell of Natchez, Miss.
1845—Elected a member of the House of Representatives of the U.S. Congress.
1846, July 21—Resigned from the House of Representatives for volunteer service with the Mississippi troops in the Mexican War; appointed Colonel of the First Mississippi Regiment which, under his heroic leadership, won great renown at Monterey and Buena Vista.
1847—Received a rousing welcome on his return from Mexico; appointed to fill a vacancy in the U.S. Senate, then elected to the Senate for the following full term.
1853-1857—Recognition given him for the outstanding worth of his services to the nation, while Secretary of War under President Franklin Pierce.
1857—Again elected to the United States Senate.
1861, January 21—Resigned from the Senate when Mississippi seceded from the Union.
1861, January 25—Commissioned Major General of the State’s Military Forces by J. J. Pettus, Governor of Mississippi.