Born on July 31, 1837 to Thomas Henry and Caroline Cornelia (Clarke) Quantrill, the boy displayed his cruel tendencies even as a child. Purportedly, this bad seed would shoot pigs through the ears just to hear them squeal, nail snakes to trees, and tie cats’ tails together for the pure joy of watching them claw each other to death.

He wasn’t to change much as he grew older. After teaching school briefly in Ohio and Illinois he fled to Kansas in 1857 to escape a horse theft charge. His initial stay in Kansas was short lived, when he accompanied an army provision train to Utah in 1858. Along the long trail to Utah, the man who had grown up in a Unionist family, met numerous pro-slavery Southerners who deeply affected his beliefs. Once in Utah, he began to use the alias of Charles Hart, lived his life as a gambler and was quickly associated with a number of murders and thefts at Fort Bridger and elsewhere in the territory. Fleeing yet again, under a warrant for his arrest, he returned to Kansas.

In December 1860, he joined a group of Kansas Free-State men who were intent upon freeing the slaves of a Missouri man by the name of Morgan Walker.  But Quantrill’s participation was only a ruse. As the Jayhawkers hid in the bush, Quantrill volunteered to “scout the area.” Soon, Quantrill, along with Walker, returned to ambush the four Kansas men, killing three of them.

When the Civil War broke out in April, 1861, Quantrill joined the Confederate side with enthusiasm. He fought with Confederate forces at the battle of Wilson's Creek in Oakhills, Missouri, in August 1861. This battle marked the beginning of the Civil War in Missouri, where the state would become the scene of savage and fierce fighting, primarily from guerilla warfare.

By late in the year, Quantrill became unhappy with the Confederates’ reluctance to aggressively prosecute the Union troops.  As a result, the young man took it upon himself to take a more antagonistic course with his own-guerilla warfare, becoming the leader of Quantrill’s Raiders. Starting with a small force of no more than a dozen men, the pro-slavery guerrilla band began to make independent attacks upon Union camps, patrols and settlements.