John Brown was an abolitionist during the antebellum period. After the sack of Lawrence, Brown convinced himself that God ordained him in the words of a neighbor "to break the jaws of the unwicked." In May of 1856 Brown led seven men, including four of his sons and son-in-law toward the Pottawatomie Creek near Lawrence. There they killed five proslavery men associated with the Lecompton government. This event is known as the Pottawatomie Massacre. This had helped complete the transformation of "bleeding Kansas" into a battleground between the south and north.

Brown came back into the picture with the raid on the federal arsenal at Harpers Ferry, Virginia in 1859. Brown with twenty-one other men seized the arsenal on October 16, 1859. The raid was to ignite a massive slave insurrection. Brown wanted to seize Virginia and then throughout the south, he thought he was God's instrument "to purge this land with blood." This failed because Brown forgot to inform the slaves about his plans and he did not have enough food to last a day. The raid was put down on October 17, when a detachment of federal troops commanded by Colonel Robert E. Lee and J.E.B. Stuart overpowered John Brown and his fellow raiders. Ten of Brown's men were killed and seriously wounded, and Brown was wounded after being stabbed by a marine.

Brown was put on trial for treason against Virginia, conspiracy with slaves, and first-degree murder. During the investigation several well-known northern abolitionist approve of Brown's plan and said they help raise money for his preparations. Brown was convicted of treason on November 2, and was sentenced to be hanged. Brown was hanged on December 2, 1859, which completed the rise to the status of a martyred saint of the anti-slavery cause.