Nathan Bedford Forrest accumulated wealth before the Civil War as a planter, businessman, and trader in enslaved people in Memphis. He entered Confederate service in 1861 and used his own resources to equip a cavalry unit. Without formal military education, he proved effective at reconnaissance, rapid movement, and raids on Union supply lines. His command escaped Fort Donelson before its surrender in February 1862, and he subsequently fought at Shiloh and conducted operations across Tennessee and neighboring states.

Forrest captured Murfreesboro in July 1862 and rose rapidly in rank. His raids challenged Union control of communications and drew enemy troops away from other operations. In 1863 he forced the surrender of Abel Streight's raiding force and participated in the Chickamauga campaign. Conflict with Braxton Bragg over command and follow-up operations helped lead to his transfer to an independent command in Mississippi and western Tennessee.

On April 12, 1864, Forrest's forces attacked Fort Pillow on the Mississippi River. Many of the Union defenders, especially Black troops, were killed after resistance collapsed. Contemporary testimony and modern scholarship identify the event as a massacre. Fort Pillow is central to his military record, alongside his tactical successes.

At Brice's Cross Roads in June 1864, Forrest defeated a larger Union expedition, exploiting terrain, weather, and the enemy's divided advance. A month later Union forces checked him at Tupelo. He continued raids, including an attack on Memphis and the destruction of a Union supply base at Johnsonville. During the disastrous Confederate invasion of Tennessee he supported John Bell Hood and helped cover the retreat. Union cavalry under James H. Wilson defeated his forces at Selma in April 1865, and Forrest surrendered the following month.

After the war he pursued railroad and business ventures with mixed results. He became associated with the early Ku Klux Klan and is widely identified as its first grand wizard, although aspects of his leadership are poorly documented. The Klan employed terror to suppress Black citizenship and Republican government. Forrest later spoke publicly in favor of some forms of racial reconciliation, but those remarks cannot erase slave trading, Fort Pillow, or his connection to racial intimidation. He died in 1877. His reputation consequently encompasses military effectiveness and sustained participation in institutions of white supremacy.