Quantrill grew up in a Unionist family and initially espoused Free-Soil beliefs. He was the oldest 0f 12 children born to an Ohio schoolteacher. Becoming a schoolteacher at the age of 16, he worked several years as a school teacher. Growing up in Ohio, he taught school in Ohio and then in Illinois. he moved to Kansas in 1857 to take up farming.
He traveled to Utah with the Federal Army in 1858, but there left the army to try his hand at professional gambling. In 1859, he returned to Lawrence, Kansas, under the assumed name of Charley Hart, and again taught school. After charges were brought against him for murder and horse theft, fled to Missouri.
By now a staunch Southern supporter, he later joined a regiment of Missouri Confederate troops just before the Civil War. Though his dislike of the strictures of army life would lead him to form the independent guerrilla band known as Quantrill's Raiders by the end of 1861.
Quantrill’s Raiders began as a force of no more than a dozen men who staged raids into Kansas from Missouri, harassing Union soldiers and sympathizers. They frequently skirmished with Jayhawks, the pro-Union guerrilla bands raiding Missouri from Kansas, as well as raiding farms and robbing mail coaches. Union forces soon declared him an outlaw, and the Confederacy officially made him a captain. Quantrill quickly became known to his opponents as a notoriously bloody raider, and to his supporters as a dashing, free-spirited hero.
The most significant event of his guerrilla career occurred on August 21, 1863, at Lawrence, Kansas. Lawrence had been seen for years as the bastion of anti-slavery forces in Kansas. In the weeks immediately preceding the raid, Union Gen. Thomas Ewing, Jr., had ordered the detention of any citizens giving aid to Quantrill's raiders. A number of female relatives of the raiders were detained in a jail in Kansas City, Missouri, which collapsed on August 14, killing 4 women. Quantrill's supporters alleged the collapse to be a deliberate attack, and the event fanned them into a fury.
These events led to Quantrill's raiders to attack the city. The raid would become notorious in the North as one of the most vicious atrocities of the Civil War.
In retaliation for the raid, Ewing authorized General Order No. 11 (not to be confused with Gen. Ulysses S. Grant's more famous General Order No. 11) evicting thousands of Missourians from their homes near the Kansas border. Quantrill's band took part in the subsequent Confederate retaliation but, in the face of continued Union advance, finally fled to Texas.
Quantrill’s band began to splinter with the retreat, breaking into several smaller units. One such was led by his vicious lieutenant, William "Bloody Bill" Anderson, who wore a necklace of Yankee scalps. In 1865, now leading only a few dozen men, Quantrill staged a series of raids into Kentucky. Quantrill was trapped in barn on the James H. Wakefield farm, about one mile from Smiley, Kentucky by Edward Terrell and his cavalry detachment of hired assassins on May 10, 1865.
While attempting to escape, he was struck by two Spencer balls, one in the hand, the other paralyzing him from the waist down.
He was then transferred to a Federal military hospital in Louisville, then to a Catholic Hospital in Louisville. After almost a month of fighting for his life, he died at the Catholic Hospital in Louisville at 4:00 P.M. on June 6th.
His actions, particularly the raid on Lawrence, remain controversial to this day. Some historians remember him as an opportunistic, bloodthirsty outlaw, while others continue to view him as a daring soldier and local folk hero. Something of this celebrity later rubbed off on several ex-Raiders—Jesse and Frank James, and Cole and Jim Younger—who went on in the late 1860s to apply Quantrill's hit-and-run tactics to bank and train robbery. The William Clarke Quantrill Society continues to research and celebrate his life and deeds. Quantrill’s raid on Lawrence figures prominently in Jane Smiley’s novel "The All-True Travels and Adventures of Lidie Newton."