James Knox Polk’s nomination to the presidency was unexpected by everyone except those who had watched the young Tennessean’s career quickly rise to prominence.

Who was this dark-horse candidate who would emerge from the political fray of the early 1840s, serve one term, oversee several major national actions, and then retire, returning home to die with months?

James was the eldest child of a strict Presbyterian, prosperous Tennessee farming family that traced its ancestral roots back to Scotland. He was never a healthy, vigorous child due to a frail constitution, but he emerged as a scholarly young man who seemed determined to compensate for his limited physical attributes by working long hours, sleeping little, and embarking on every task as though it was the most important job of the moment.

Homeschooled by his mother and a series of tutors, James entered the University of North Carolina as a sophomore in 1816 and, two years later, was recognized as a honor graduate. He then studied law with Felix Grundy (later the U.S. attorney general during the Van Buren administration), passed the bar in 1820, and immediately went to work for the Tennessee legislature. As the legislative clerk who handled proposed bills and worked closely with members of the Senate, he developed friendships with individuals who could later advise and counsel his political choices.

Only three years later, Polk was seated as a member of the Tennessee House of Representatives as a Jeffersonian Republican, where he was tapped as the chief legislative lieutenant for Governor William Carroll. He served one term, was then elected to the U.S. House of Representatives, and would be reelected six additional times. In 1835, with influence from his fellow Tennessean, President Andrew Jackson, Polk was elected speaker of the House.

His rise to prominence had been almost meteoric.

In 1839, Polk returned home to acclaim to serve as Tennessee’s governor, but the economic upheavals of the late 1830s doomed his attempts to reform banking and financial protocols. No longer possessing a political post, Polk returned to life on the family plantation with his beloved Sarah Childress Polk, his strongest supporter in all endeavors. Well-educated and wealthy, Sarah was the perfect counterweight to her quiet and often shy husband. Invitations to her parties and conversations with the witty and lively Sarah became the most prized social engagements in Nashville and Washington, DC.

So how did the quiet planter from Tennessee, retired from politics, find himself propelled into the national spotlight once again? It’s a fascinating story…

The Democratic Party held its national convention in Baltimore in 1844. Incumbent candidate President Martin Van Buren seemed to have the nomination in his pocket, but that was not the case. His age and his opposition to the annexation and statehood of Texas sealed his fate. Van Buren understood the risk — Southern states were lobbying for immediate action on Texas, but Northern states, like his home state of New York, saw the admission of Texas as a win for the slave-holding Southern bloc. His hope was that, while he might not be anyone’s favorite, there were no other viable candidates.

Wrong. So very wrong.

While Lewis Cass, former secretary of war during the Jackson administration, arrived at the convention with four states promising their votes to him, he did not appear to be a formidable opponent. But when the voting began, each set of ballots saw Cass’s votes increasing until on the fifth ballot, Cass moved ahead. Angry at the disloyalty of the party he had served, Van Buren tossed his support to the country’s first dark-horse candidate, former Speaker of the House James K. Polk.

Within hours, George Dallas of Pennsylvania was named the vice presidential candidate and confirmed the party platform that included “reoccupation of Oregon and annexation of Texas” along with no federal interference in the “domestic institutions” of the states — code for the issue of slavery. Polk vowed to serve only one term.

In short order, the Whigs nominated Henry Clay. He was the “always the bridesmaid and never the bride” presidential candidate, and 1844 would prove to uphold that descriptor. When Theodore Frelinghuysen joined the ticket, the battle lines were drawn. Frelinghuysen was an evangelical Christian leader and vehemently opposed slavery, and the annexation of Texas and his nomination confirmed the South’s greatest fears.

The election was complicated by the emergence of a third candidate, James G. Birney of Michigan of the Liberty Party, who also “hated” Henry Clay.

It’s about to get interesting.