James Buchanan was born in Cove Gap, Pennsylvania, on April 23, 1791. He was the second of 11 children born to James Buchanan, Sr., a businessman and native of Ireland, and Elizabeth Speer Buchanan. Buchanan grew up on his father's frontier trading post in Stony Batter, near Mercersburg, Pennsylvania. Although Anne Caroline Coleman became his fianc?? in 1819, gossip caused Anne to break the engagement, and she committed suicide one week later. He never married.

After learning arithmetic and bookkeeping at his father's store and acquiring a strong Presbyterian sense of patriotism and scholarly desire from his mother, Buchanan attended Dickinson College in Carlisle, Pennsylvania. He graduated with honors in 1809 and began practicing law in 1812. Buchanan served briefly in the War of 1812 and served in the Pennsylvania Assembly as a Federalist from 1814 to 1816. Despite declining prospects brought on by the death of the Federalist Party, Buchanan was elected to Congress in 1820. He served five terms in the House of Representatives from 1821 to 1831 and was elected chairman of the House Judiciary Committee. Buchanan supported Andrew Jackson in his loss to John Quincy Adams in 1824. When Jackson was elected to the presidency in 1828, Buchanan was appointed minister to Russia and negotiated the first treaty between the United States and Russia. In 1834, Buchanan was elected to the U.S. Senate and served there for the next 11 years, eventually becoming chairman of the Foreign Relations Committee.

Buchanan attempted to smooth conflicts with Mexico, England, and Oregon, as Secretary of State under President Polk in 1845. After Zachary Taylor succeeded Polk in 1848, Buchanan began planning his own 1852 presidential campaign. Buchanan became minister to Great Britain and attempted to settle problems with the Ostend Manifesto of 1854. After he signed the Manifesto, Americans were led to believe that Buchanan was solely responsible for political turmoil with Cuba.

Buchanan ran unsuccessfully for president in 1844, 1848, and 1852 before he was finally elected in 1856. He was elected as the Democratic candidate over Republican John C. Fremont. As the debates over slavery raged in the North and South, Buchanan asked Congress to approve the Lecompton Constitution and make Kansas a temporary slave state. However, Buchanan later agreed to the bill sponsored by Rep. William English of Indiana that eventually admitted Kansas as a free state in 1861. In 1860, the tension between Buchanan and Stephen A. Douglas split the Democratic Party, adding to President Buchanan's unpopularity. The Republican Party elected its first president, Abraham Lincoln, in 1860. The election of the Northern abolitionist caused the South's secession, and the Civil War commenced.

Buchanan remained a Union supporter, but was anxious to leave politics behind. In 1866, Buchanan's autobiography,Mr. Buchanan's Administration on the Eve of the Rebellion, was published. He retired and remained at his estate, "Wheatland," near Lancaster, Pennsylvania until his death on June 1, 1868.