Howell Cobb was born in 1815 in Cobbham (Jefferson County), Georgia. He graduated from Franklin College (now the University of Georgia) in 1834 before studying the law and being admitted to the state bar in 1836. A year later, Cobb was serving as solicitor general of the Western Circuit Court of Georgia, a post he held until 1841.

After an unsuccessful run for the United States House of Representatives in 1840, Cobb won his election two years later and served in Congress from 1843 to 1851 as a moderate Democrat. In his final term in the House, Cobb served as Speaker and played an important role in negotiating and securing the passage of the Compromise of 1850.

Cobb resigned from Congress in 1851 and returned to Georgia, where he defended the compromise and became governor, a post he held from 1851 to 1853. One year later, he returned to the United States Congress (1855-1857) until President James Buchanan tapped him to become his secretary of the treasury. Cobb served in that post from 1857 to 1860, devoting most of his attention to issues surrounding the Panic of 1857. In 1860, Cobb made a failed attempt at becoming the Democratic nominee for President and saw his party split into two factions over the issue of slavery.

Following the election of Republican Abraham Lincoln as President, Cobb resigned his cabinet post, returned to Georgia, and led his state to secession. He then served as president of the convention establishing a provisional Confederate government. In 1861, he administered the oath of office to Confederate president Jefferson Davis and vice president Alexander H. Stephens. After presiding over the provisional congress, Cobb failed to secure a seat in the new government; instead, he served the Confederacy as a brigadier general and ultimately as a major general, though he saw no action.

Following the war, Cobb was pardoned by President Andrew Johnson and resumed his law practice in an effort to offset his financial troubles. Howell Cobb died in 1868.