Hannibal Hamlin was born to Cyrus Hamlin and Anna Livermore in Paris, Maine August 27, 1809. He was a descendant in the sixth generation of James Hamlin who had settled in the Massachusetts Bay Colony in 1639. Hamlin was a great nephew of U.S. Senator Samuel Livermore II of New Hampshire, and a grandson of Stephen Emery, Maine's Attorney General in 1839–1840.
Hannibal Hamlin attended the district schools and Hebron Academy and later managed his father's farm. For the next few years he worked at several jobs: schoolmaster, cook, woodcutter, surveyor, manager of a weekly newspaper in Paris, and a compositor at a printer's office.
Hannibal's ambition to become a lawyer was nearly sidetracked, first when his elder brother took ill, forcing him to leave school to run the family farm, and then when his father died, requiring him, under the terms of his father's will, to stay home and take care of his mother until he turned twenty-one. When he came of age, however, Hannibal left home to read law at the offices of Fessenden and Deblois, under Samuel C. Fessenden, an outspoken abolitionist and father of Hamlin's future political rival, William Pitt Fessenden. The association made Hamlin an antislavery man and launched him into his new profession. He set up his own law practice and became the town attorney in Hampden, Maine.
Hannibal Hamlin married Sarah Jane Emery of Paris Hill in 1833. After Sarah died in 1855, he married her half-sister, Ellen Vesta Emery in 1856. He had four children with Sarah: George, Charles, Cyrus and Sarah, and had two children, Hannibal E. and Frank, with Ellen. Ellen Hamlin died in 1925.
Politically, from the 1830s to the 1850s, Maine was an entrenched Democratic state, and the politically ambitious Hamlin joined the Democratic party. In 1835 he was elected to the state house of representatives. His most notable legislative achievement was to lead the movement to abolish capital punishment in Maine. In 1840 he lost a race for the U.S. House of Representatives, but in 1843 he won a seat in Congress. There he denounced Henry Clay's economic programs and voted very much as a Jacksonian Democrat. He became chairman of the Committee on Elections and won a coveted seat on the House Rules Committee.
Hamlin and Jefferson Davis sparred frequently in the House and Senate over slavery. Tempers between the two men rose to such a level that for the only time in his life Hamlin thought it prudent to carry a pistol for self-protection. The unexpected death of Senator John Fairfield from malpractice by an incompetent physician opened a Senate seat from Maine, which Hamlin was elected to fill in 1848. That same year, antislavery Whigs and Democrats united to form a Free Soil party that nominated Martin Van Buren for president. Although Hamlin approved of their antislavery platform and had supported Van Buren in the past, he could not bring himself to abandon his party—to which he owed his Senate seat. As a Democratic senator, Hamlin strongly opposed Henry Clay's proposed Compromise of 1850. If the bill spread slavery into the West, he declared, "it will not be with my vote."
After the Democratic Party endorsed the Kansas-Nebraska
Act, which repealed the Missouri Compromise at the 1856 Democratic National Convention, on June 12, 1856,
Hannibal Hamlin withdrew from the Democratic Party and joined the newly organized Republican Party, causing a national sensation.
The Republicans nominated him for Governor of Maine in the same year. He carried the election by a large majority and was inaugurated on January 8, 1857. In the latter part of February 1857, however, he resigned the governorship, and was again a member of the United States Senate from 1857 to January 1861.
Abraham Lincoln's first vice president, Hannibal Hamlin, was a distinguished New England politician who served six terms in the Maine legislature (1836-40 and 1847); represented his state in the House of Representatives for two terms; and interrupted his second term in the U.S. Senate in 1857 to serve as governor of Maine, a position he soon resigned to re-enter the Senate. The Republican Party picked him to be Abraham Lincoln's running mate mostly for geographical reasons; they needed an East Coast politician to balance Lincoln's Midwest roots, and Hamlin's non-existent legislative record as a House representative, a U.S. Senator and Maine's Governor made him a safe choice.
Before his nomination, Hamlin had never met Lincoln. Hamlin had not wanted the vice presidency. Having traded his influential Senate seat for a traditionally powerless office, he hoped to be assigned some important function in the Lincoln government. Although the president listened to his views, which included his urging the issuance of the Emancipation Proclamation and the enlisting of free blacks in the army, Hamlin was relegated to the background. Hamlin resented his idleness, but he did not want to be replaced as vice president. When the president and his advisors decided it would be politically expedient to name Andrew Johnson, military governor of Tennessee, to the vice-presidential spot in 1864, Hamlin was again disappointed.
After his vice presidency, Hamlin was collector of customs for the port of Boston, served again in the Senate (1869-81), and concluded his public career by serving as minister to Spain (1881-82) during the Arthur administration. He died suddenly on July 4, 1891, at his club in Bangor.