He was a large man who walked with a swagger. Despite his limited formal education, he built a flourishing law practice and rose rapidly in the world of Indiana Democratic politics. Abrupt and hot-tempered, he was among the shrewdest of his state's political figures.

By 1845, Jesse Bright had become president of the Indiana state senate. Capitalizing on an opportunity to break a tied vote on the selection of a United States senator, he engineered his own election to that office.

In the Senate, Bright's knowledge of the chamber's rules and precedents won him the post of president pro tempore on several occasions. In the 1850s, however, he lost many of his natural political allies who were uncomfortable with his increasing support of legislation to protect slavery in the nation's territories. By 1860, his ownership of a Kentucky farm and 20 slaves led antislavery Indiana legislators to consider asking the Senate to declare his seat vacant. As southern states began to leave the Union, Bright opposed the use of force against them because he believed they would soon return.

The July 1861 Battle of Bull Run proved a disaster for Union troops—and for Jesse Bright. During the battle, Union forces captured an arms merchant as he attempted to cross into Confederate territory. They discovered that he carried a letter of introduction to Confederate president Jefferson Davis. The letter, highly deferential in tone, was signed by United States Senator Jesse Bright.

When the Senate took up the matter in January 1862, Bright explained that the captured arms supplier was a former client of his law practice. Although he claimed not to remember writing the letter, he asserted that it was only natural to introduce a friend to Davis, until recently a Senate colleague. Finally, Bright noted that the letter was dated March 1—before any fighting began. Aware that the Senate's Republican majority caucus had already determined his fate, Bright took the Senate floor on February 5, 1862, to state his case, if only "for posterity." He then gathered his belongings and walked solemnly from the chamber. Moments later, by a vote of 32 to 14, Bright became the 14th and final senator expelled by the Senate during the Civil War. No senator has been expelled since his time.

After a doomed Senate reelection bid, Bright served in the Kentucky legislature and went on to earn a fortune from his investments in West Virginia coal mines.