Born December 6, 1833, in Powhatan County, VA, John Singleton Mosby was the son of Alfred and Virginny Mosby. At the age of seven, Mosby and his family moved to Albemarle County near Charlottesville. Educated locally, Mosby was a small child and was frequently picked upon, however he rarely backed down from a fight. Entering the University of Virginia in 1849, Mosby proved to be an able student and excelled at Latin and Greek. While a student, he became involved in a fight with a local bully, during which he shot the man in the neck.
Expelled from school, Mosby was convicted of unlawful shooting and sentenced to six months in jail and a $1,000 fine. Following the trial, several of the jurors petitioned for Mosby's release and on December 23, 1853, the governor issued a pardon. During his brief time in jail, Mosby befriended the local prosecutor, William J. Robertson, and indicated an interest in studying law. Reading law at Robertson's office, Mosby was finally admitted to the bar and opened his own practice in nearby Howardsville, VA. Shortly thereafter, he met Pauline Clarke and the two were married on December 30, 1857.
Settling in Bristol, VA, the couple had two children prior to the outbreak of the Civil War. Initially an opponent of secession, Mosby immediately enlisted in the Washington Mounted Rifles (1st Virginia Cavalry) when his state left the Union. Fighting as a private at the First Battle of Bull Run, Mosby found that military discipline and traditional soldiering were not to his liking. Despite this, he proved an able cavalryman and was soon promoted to first lieutenant and made adjutant of the regiment.
As the fighting shifted to the Peninsula in the summer of 1862, Mosby volunteered to serve as a scout for Brigadier General J.E.B. Stuart's famed ride around the Army of the Potomac. Following this dramatic campaign, Mosby was captured by Union troops on July 19, 1862, near Beaver Dam Station. Taken to Washington, Mosby carefully observed his surroundings as he was moved to Hampton Roads to be exchanged. Noticing ships bearing Major General Ambrose Burnside's command arriving from North Carolina, he immediately reported this information to General Robert E. Lee upon being released.
This intelligence assisted Lee in planning the campaign that culminated in the Second Battle of Bull Run. That fall, Mosby began lobbying Stuart to allow him to create an independent cavalry command in Northern Virginia. Operating under the Confederacy's Partisan Ranger Law, this unit would conduct small, fast-moving raids on the Union lines of communication and supply. Seeking to emulate his hero from the American Revolution, partisan leader Francis Marion (The Swamp Fox), Mosby finally received permission from Stuart in December 1862, and was promoted to major the following March.
Recruiting in Northern Virginia, Mosby created a force of irregular troops which were designated partisan rangers. Consisting of volunteers from all walks of life, they lived in the area, blending in with the populace, and came together when summoned by their commander. Conducting night raids against Union outposts and supply convoys, they struck where the enemy was weakest. Though his force grew in size (240 by 1864), it was seldom combined and often struck multiple targets in the same night. This dispersion of forces kept Mosby's Union pursuers off balance.
On March 8, 1863, Mosby and 29 men raided the Fairfax County Court House and captured Brigadier General Edwin H. Stoughton while he slept. Other daring missions included attacks on Catlett Station and Aldie. In June 1863, Mosby's command was redesignated the 43rd Battalion of Partisan Rangers. Though pursued by Union forces, the nature of Mosby's unit allowed his men to simply fade away after each attack, leaving no trail to follow. Frustrated by Mosby's successes, Lieutenant General Ulysses S. Grant issued an edict in 1864, that Mosby and his men were to be designated outlaws and hung without trial if captured.
As Union forces under Major General Philip Sheridan moved into the Shenandoah Valley in September 1864, Mosby began operating against his rear. Later that month, seven of Mosby's men were captured and hung at Front Royal, VA by Brigadier General George A. Custer. Retaliating, Mosby responded in kind, killing five Union prisoners (two others escaped). A key triumph occurred in October, when Mosby succeeded in capturing Sheridan's payroll during the "Greenback Raid." As the situation in the Valley escalated, Mosby wrote to Sheridan on November 11, 1864, asking for a return to the fair treatment of prisoners.
Sheridan agreed to this request and no further killings occurred. Frustrated by Mosby's raids, Sheridan organized a specially equipped unit of 100 men to capture the Confederate partisan. This group, with the exception of two men, was killed or captured by Mosby on November 18. Mosby, promoted to colonel in December, saw his command rise to 800 men, and continued his activities until the end of the war in April 1865. Unwilling to formally surrender, Mosby reviewed his men for the last time on April 21, 1865, before disbanding his unit.
Following the war, Mosby angered many in the South by becoming a Republican. Believing that it was the best way to help heal the nation, he befriended Grant and served as his presidential campaign chair in Virginia. In response to Mosby's actions, the former partisan received death threats and had his boyhood home burned down. In addition, at least one attempt was made on his life. To help protect him from these dangers, Grant appointed him as US Consul to Hong Kong in 1878. Returning to the US in 1885, Mosby worked as a lawyer in California for the Southern Pacific Railroad, before moving through a variety of governmental posts. Last serving as Assistant Attorney General in the Department of Justice (1904-1910), Mosby died in Washington DC on May 30, 1916, and was buried at Warrenton Cemetery in Virginia.