He spent his boyhood in Ohio. His life was a succession of business failures, in Ohio, Pennsylvania, Massachusetts, and New York, before he became prominent in the 1850s. An ardent abolitionist (he once kept a station on the Underground Railroad at Richmond, Pa.), Brown in 1855 settled with five of his sons in Kansas to help win the state for freedom. He became “captain” of the colony on the Osawatomie River.
The success of the proslavery forces, particularly their sack of Lawrence, aroused Brown, and in order “to cause a restraining fear” he, with four of his sons and two other men, deliberately murdered five proslavery men living on the banks of the Pottawatomie Creek. In this he asserted he was an instrument in the hand of God. His exploits as a leader of an antislavery band received wide publicity, especially in abolitionist journals, and as Old Brown of Osawatomie he became nationally known.
Late in 1857 he began to enlist men for a project that he apparently had had in mind for some time and that took definite form at a convention of his followers held at Chatham, Ont., the next spring. He planned to liberate the slaves through armed intervention by establishing a stronghold in the Southern mountains to which the slaves and free blacks could flee and from where further insurrections could be stirred up. Early in 1859, Brown rented a farm near Harpers Ferry, Va. (now W.Va.), and there collected his followers and arms.
On the night of Oct. 16, with 21 followers, he crossed the Potomac and without much resistance captured the U.S. arsenal at Harpers Ferry, made the inhabitants prisoners, and took general possession of the town. Strangely enough, he then merely settled down, while the aroused local militia blocked his escape. That night a company of U.S. marines, commanded by Col. Robert E. Lee, arrived, and in the morning they assaulted the engine house of the armory into which Brown's force had retired. In the resulting battle, 10 of Brown's men were killed, and Brown himself was wounded.
News of the raid aroused wild fears in the South, and to the North it came as a great shock. On Dec. 2, 1859, Brown was hanged at Charles Town. His dignified conduct and the sincerity of his calm defense during the trial won him sympathy in the North and led him to be regarded as a martyr.
The standard contemporary account is contained in The Life, Trial and Execution of Captain John Brown (1859, repr. 1969). See also biographies by O. G. Villard (rev. ed. 1965), S. B. Oakes (1970), and J. Abels (1971); A. Keller, Thunder at Harper's Ferry (1958); J. C. Malin, John Brown and the Legend of Fifty-Six (1942, repr. 1970); R. O. Boyer, The Legend of John Brown (1973).