John Brown was born in Torrington, Connecticut, on May 9, 1800. His family moved to Hudson, Ohio, in 1805, where his father, Owen, worked as a tanner converting hides into leather. Brown and his father (both white men who strongly opposed slavery) later worked together, but the younger Brown left during the winter of 1816-1817 to attend the Morris Academy in Litchfield County, Connecticut, with the intent to become part of the Congregational ministry. However, he left Morris before finishing his training and returned to work as a tanner in Hudson. On June 21, 1820, Brown married Dianthe Lusk, who would give birth to seven of his children.

Brown lived in many places during his lifetime, moving a total of 10 times. In May of 1825, he moved his family from Ohio to Crawford County, Pennsylvania, 12 miles northeast of Meadville. He lived for 10 years in Randolph Township of Crawford County where he built a tannery and a house that contained a secret room that Brown used to hide fugitive slaves who had escaped. In August of 1832, Dianthe died while giving birth to a son, who also died. On July 14, 1833, Brown married his second wife, Mary Ann Day, who was 17 at the time and the sister of Brown's housekeeper. Mary Ann would give birth to 13 of Brown's children.

In May of 1835, Brown moved his family back to Ohio to build a new tannery with a partner, possibly because he was in need of money. Over the next several years, Brown contributed much to the antislavery movement. In 1850, he worked for the United States League of Gileadites, an organization that tried to serve as a defense against slave-catchers. In 1855, Brown and five of his sons helped to defend the antislavery town of Lawrence in the Kansas Territory when it was attacked by pro-slavery forces trying to gain control over the town. His leadership in Kansas made him a well-known abolitionist throughout the United States.

In May of 1858, Brown was in Boston when he met a group of six radical abolitionists, all members of the Boston elite, who had heard of Brown and wanted to help him in his fight against slavery. These men, who became known as the "Secret Six," aided Brown by financing his undertakings. Brown told them he was planning to invade Virginia and thereby spur an uprising amongst the slaves; he hoped slaves would join him and form an emancipation army that would fight for the liberation of slaves. During this time, Brown wrote several letters to his family and his scattered supporters, informing them of his actions, successes, and plans. (Many of these letters have been preserved in full.) He also made speeches to gain support, especially in Chambersburg, Pennsylvania, where he did much of the planning for his raid on Virginia.

After some delays, Brown took action on October 16, 1859. That night Brown led 21 men (five black and 16 white) into the town of Harper's Ferry, Virginia. By early the next morning, they had seized the town's arsenal, but a militia had arrived and began firing on Brown's company. Just before midnight, Robert E. Lee arrived with more men and renewed the attack the next morning, October 18, after Brown refused to surrender. Brown was wounded, two of his sons were killed, and the remaining raiders were soon captured.

Brown was transferred to Charlestown, Virginia, where he was tried on October 28, 1859. He was charged with insurrection, treason, and murder; he was found guilty of all three. Brown was sentenced on November 2 and, in response, made a speech in front of the court. He remained loyal to the fight against slavery, asserting that he felt no guilt for trying to free slaves. Brown also said he believed he would not have been so severely punished if those he fought for were white instead of black.

John Brown was hanged on December 2, 1859, in Charlestown. The song "John Brown's Body" commemorates the raid he led on Harper's Ferry and became a popular marching song of Republican soldiers when the American Civil War began in 1861.