
As the 1852 presidential election approached, the Democrats were divided over the issue of slavery. When the Democrats met in Baltimore on June 1, as expected the convention deadlocked. It was hard for the party to agree on a candidate who would be acceptable to north and south. On the first ballot, with 288 delegates voting, 116 of them voted for Lewis Cass of Michigan, and 93 voted for former Secretary of State James Buchanan> The rest were scattered, without a single vote for Pierce. Another 34 ballots passed with no one near victory, and still no votes for Pierce. The Buchanan team decided to have their delegates vote for minor candidates, including Pierce, to demonstrate that no one but Buchanan could win. The plan backfired, as delegates from Virginia, New Hampshire, and Maine switched to Pierce, and before long Pierce was in third place. After the 48th ballot, North Carolina Congressman James C. Dobbin delivered a passionate speech endorsing Pierce, and on the 49th ballot, Pierce won the nomination, receiving all but six votes
The Whig Party rejected incumbent President Millard Fillmore, and nominated General Winfield Scott, under whom Pierce had served under in the Mexican-American War. The platforms of the two parties were very similar as they both tried to straddle the issues to attract support from all factions and all regions of the country. Both included support of the Compromise of 1850. The Free Soil Party, an anti-slavery group, nominated Senator John P. Hale of New Hampshire as their candidate. According to Pierce biographer Peter A. Wallner, this was "one of the least exciting campaigns in presidential history".
Pierce emerged victorious in the election. Scott won only Kentucky, Tennessee, Massachusetts and Vermont, finishing with 42 electoral votes to Pierce's 254. With 3.2 million votes cast, Pierce won the popular vote with 50.9 to 44.1 percent. The transition from candidate to president began tragically for Pierce. On January 6, 1853, his family was traveling from Boston by train when their car derailed and rolled down an embankment near Andover, Massachusetts. Franklin Pierce and his wife Jane survived, but their only son, 11-year-old Benjamin was crushed to death. The Pierces had two previous sons die in infancy and when their only remaining child died, they both suffered severe depression as a result. Pierce tried to cope with alcohol and Jane by isolation. She saw the train accident as divine punishment for her husband's pursuit and acceptance of high office. She wrote a lengthy letter of apology to her late son and she stayed in New Hampshire as Pierce left for his inauguration. Pierce, the youngest man to be elected president to that point, chose to affirm his oath of office on a law book rather than swear it on a Bible, as all his predecessors except John Quincy Adams had done.
In his Cabinet appointments, Pierce wanted to unite the Democratic Party by appointing Democrats from all party factions, even those that had not supported the Compromise of 1850. His most trusted advisors in the cabinet were Attorney General Caleb Cushing, a pro-compromise northerner, and Secretary of War Jefferson Davis, who had led Southern resistance to the compromise in the Senate. Cushing had just lost a race to become Governor of Massachusetts. Like Pierce, he was what was known as a "doughface", i.e., a Northerner with Southern sympathies. At the end of the Pierce Presidency, when the Dred Scott decision was handed down, Chief Justice Roger B. Taney, who wrote the decision, wrote Cushing a letter thanking him for his support.
Pierce and Davis had served together in the Mexican War. The two men became good friends and Mrs. Varina Davis filled in for Jane Pierce in performing some of the ceremonial duties that the first lady was responsible for. The two remained friends even when Davis was President of the Confederacy. When the Mississippi plantation belonging to Davis was seized by Union soldiers,. Pierce's correspondence with Davis (all written before the war) was discovered, revealing their close friendship, harming Pierce's reputation among northerners.
For the key position of Secretary of State, Pierce chose William L. Marcy. Marcy had served as Secretary of War under President James K. Polk. He was a leader of the "Hunker" faction of the New York Democratic Party, the wing that opposed the one led by Martin Van Buren. Pierce tried to appease supporters of Lewis Cass and James Buchanan by making cabinet appointments acceptable to their sections of the party. Pierce appointed Secretary of the Interior Robert McClelland of Michigan, a Cass supporter, and Postmaster General James Campbell of Pennsylvania, a Buchanan man. Pierce rounded out his geographically-balanced cabinet with Secretary of the Navy James C. Dobbin of North Carolina and Secretary of the Treasury James Guthrie of Kentucky. Guthrie became the most influential member of Pierce's cabinet, in part because of the patronage power that came with the position. He was a hard money Democrat who opposed a national bank. He called for the adoption of a universal currency that would be convertible to gold on demand.
All of Pierce's cabinet nominations were confirmed unanimously and immediately by the Senate. Like other presidents of that era, Pierce spent the first few weeks of his term sorting through hundreds of lower-level federal positions to be filled by hungry office-seekers. He tried to represent all factions of the party, only to discover that he could fully satisfy any of them. Northern newspapers accused Pierce of filling his government with pro-slavery secessionists, while southern newspapers accused him of catering to the abolitionists. Within the New York Democratic Party, the conservative Hardshell Democrats or "Hards" of New York were deeply skeptical of the Pierce administration because he had given such an important cabinet post to Marcy, the member of the more moderate New York faction.

Pierce wasn't a complete failure as President. He tried to run a more efficient and accountable government than his predecessors and he had his Cabinet members implement a system of civil service examinations. Interior Secretary Robert McClelland tried to weed out fraud in his department. Pierce expanded the role of the Attorney General in appointing federal judges and attorneys, an important step in the eventual creation of the Justice Department. He signed trade treaties with Britain and Japan, and his Cabinet reformed their departments and improved accountability. But these minor successes were overshadowed by what went wrong during his presidency.
His popularity declined rapidly in the Northern states after he supported the Kansas–Nebraska Act, which led to violent conflict over the expansion of slavery in the American West. Pierce's administration was further damaged when several of his diplomats issued the Ostend Manifesto calling for the annexation of Cuba, by force if necessary. Pierce hoped to be renominated by the Democrats in the 1856 presidential election, but he was abandoned by his party. In his despair at the end of his political career, he is reported to have said, when asked what he was going to do now, “There’s nothing left to do but get drunk.”