See C. W. Russell, ed., The Memoirs of Colonel John S. Mosby (1917, repr. 1969); biographies by V. C. Jones (1944), J. Daniels (1959), K. Seipel (1983), and J. A. Ramage (1999).
Mosby began his education at a school called Murrell's Shop. When his family moved to Albemarle County, Virginia (near Charlottesville) about 1840, John attended school in Fry's Woods before transferring to a Charlottesville school at the age of ten. Because of his small stature and frail health, throughout his school career Mosby was the victim of bullies. Instead of becoming withdrawn and lacking in self confidence, the boy responded by fighting back although—as he admitted in his memoirs—he never won any fight in which he was engaged. The only fight he did not lose in these schoolboy melées was with a boy who remained his friend in later life. An adult stepped in and separated the combatants.
In 1849, Mosby entered the University of Virginia, taking Classical Studies and joining the Washington Literary Society and Debating Union. He was far above average in Latin, Greek, and literature (all of which he enjoyed), but mathematics was a problem for him. In his third year, a quarrel erupted between Mosby and a notorious bully, George R. Turpin, a tavern keeper's son who was robust and physically impressive. Turpin was supposedly a medical student at the university, but he and his comrades attacked other students. In one case, Turpin took a knife to a small student, and in another, he almost killed a much smaller youth with a rock. When Mosby heard that Turpin had insulted him to a friend, Mosby sent Turpin a letter asking for an explanation—one of the rituals in the code of honor to which Southern gentlemen adhered. Turpin became enraged and declared that on their next meeting, he would "eat him [Mosby] up raw!" Mosby decided he had to meet Turpin despite the risk; to run away would be dishonorable.
On March 29 the two met, Mosby having brought with him a small 'pepperbox' pistol in the hope of dissuading Turpin from an attack. When the two met and Mosby said, "I hear you have been making assertions ...," Turpin put his head down and charged. At that, Mosby pulled out the pistol and shot his adversary in the neck. The distraught 19-year-old Mosby went home to await his fate. Mosby was arrested and arraigned on two charges: unlawful shooting (a misdemeanor with a maximum sentence of one year in jail and a $500 fine) and malicious shooting (a felony with a maximum sentence of 10 years in the penitentiary). After a trial that almost resulted in a hung jury, Mosby was convicted of the lesser offense, but received the maximum sentence—a year in the Charlottesville jail and a fine of five hundred dollars. Mosby later discovered that he had been expelled from the university before he was brought to trial. There is nothing to suggest that Turpin, for all of his former violence, was likewise expelled for his notorious past.
While serving time, Mosby won the friendship of his prosecutor, attorney William J. Robertson. When Mosby expressed his desire to study law, Robertson offered the use of his law library. Mosby studied law for the rest of his incarceration. Immediately after the sentence had been handed down, nine of the twelve jurors began a petition for his pardon. Two of the jurors were against the young man; one hated students of the university and found Mosby's trial an opportunity to make a statement to that effect. The other juror hated Mosby's father Alfred. In addition to this petition and others from the university, Mosby's parents submitted sworn statements by several physicians noting that given the frail state of Mosby's health, the twelve-month sentence might risk his life. Mosby was beginning to sicken as the weather grew cold and he suffered in the small, unhealthy jail. On December 23 1853, the governor pardoned Mosby, and in early 1854, his fine was rescinded.
About this time, Mosby met Pauline Clarke, who was visiting from out of town. He was Methodist and she was Catholic, and their courtship ensued. Her father was an active attorney and well-connected politician. They were married in a Nashville, hotel on December 30, 1857, with their wedding attended by Andrew Jackson, among other dignitaries. After living for a year with Mosby's parents, the couple settled in Bristol, Virginia, (close to Clarke's hometown in Kentucky). They had two children before the Civil War and another born during it.
Mosby spoke out against secession, but joined the Confederate army as a private at the outbreak of the war. He first served in William "Grumble" Jones's Washington Mounted Rifles. (Jones became a major and was instructed to form a more collective "Virginia Volunteers", which he created with two mounted companies and eight companies of infantry and riflemen including the Washington Mounted Rifles.) Mosby was upset with the Virginia Volunteers' lack of congeniality and he wrote to the governor requesting to be transferred. However, his request was not granted. The Virginia Volunteers participated in the First Battle of Bull Run.
After impressing J.E.B. Stuart with his scouting ability, Mosby was promoted to first lieutenant and assigned to Stuart's cavalry scouts. He helped the general develop attack strategies. He was responsible for Stuart's "Ride around McClellan" during the Peninsula Campaign. Captured by Union cavalry, Mosby was imprisoned in the Old Capitol Prison in Washington, D.C., for ten days before being exchanged. Even as a prisoner, Mosby spied on his enemy. During a brief stopover at Fort Monroe, he detected an unusual buildup of shipping in Hampton Roads. He found they were carrying thousands of troops under Ambrose Burnside from North Carolina on their way to reinforce John Pope in the Northern Virginia Campaign. When he was released, Mosby walked to army headquarters outside Richmond and personally related his findings to Robert E. Lee.
In January 1863, Stuart, with Lee's concurrence, authorized Mosby to form and take command of the 43rd Battalion Virginia Cavalry, Partisan Rangers. This was later expanded into Mosby's Command, a regimental-sized unit of partisan rangers operating in Northern Virginia. The Confederate government certified special rules to govern the conduct of partisan rangers. These included sharing in the disposition of spoils of war. Having previously been promoted to Captain (March 15, 1863) and Major (March 26, 1863) in the Provisional Army of the Confederate States, Mosby was soon promoted to Lieutenant Colonel on January 21, 1864 and to Colonel, December 7, 1864.
Mosby's group consisted of Fount Beatie, Charles Buchanan, Christopher Gaul, William L. Hunter, Edward S. Hurst, Jasper and William Jones, William Keys, Benjamin Morgan, George Seibert, George M. Slater, Daniel L. Thomas, William Thomas Turner, Charles Wheatley, and John Wild. He and his men carried out the Greenback Raid and attacked Maj. Gen. Philip Sheridan's wagon train at Berryville.
Mosby is famous for carrying out a daring raid far inside Union lines at the Fairfax County courthouse in March 1863, where his men captured three high-ranking Union officers, including Brig. Gen. Edwin H. Stoughton. The story is told that Mosby found Stoughton in bed and roused him with a slap to his rear. Upon being so rudely awakened, the general shouted, "Do you know who I am?" Mosby quickly replied, "Do you know Mosby, general?" "Yes! Have you got the rascal?" "No but he has got you!" His group also captured about 30 to 50 sentries without firing a shot.
Mosby's successful disruption of supply lines and attrition of Union couriers caused General Grant to tell Sheridan, "When any of Mosby's men are caught, hang them without trial." On September 22, 1864, Union forces that Mosby believed (not necessarily correctly) to be commanded by, and acting with the knowledge of, Union Brig. Gen. George A. Custer executed six of Mosby's men in Front Royal, Virginia; a seventh was executed on a subsequent occasion. William Thomas Overby was one of the men selected for execution on the hill in Front Royal. His captors offered to spare him if he would reveal Mosby's location, but he refused. According to reports at the time, his last words were, "Mosby will hang 10 of you for every one of us." After his death, a Union soldier pinned a piece of paper on his shirt that read: "Such is the fate of all of Mosby's gang."
After informing General Robert E. Lee and Confederate Secretary of War James A. Seddon of his intention to respond in kind, Mosby ordered seven Union prisoners, chosen by lot, to be executed in retaliation on November 6, 1864, at Rectortown, Virginia. The soldiers charged with carrying out the orders hanged three men; they shot two more in the head and left them for dead (remarkably, both survived); the other two condemned men managed to escape. On November 11, 1864, Mosby wrote to Sheridan as the commander of Union forces in the Shenandoah Valley, requesting that both sides resume treating prisoners with humanity. He pointed out that he and his men had captured (and returned) far more of Sheridan's men than they had lost. The Union side complied. With both camps treating prisoners as "prisoners of war" for the duration, there were no more executions.
Several weeks after General Robert E. Lee's surrender, Mosby simply disbanded his rangers, as he refused to surrender formally. Mosbys' Rangers however were the carriers of the surrender orders and documents to Appomattox Court House.
After the war, Mosby became an active Republican, saying it was the best way to help the South. Mosby went on to become a campaign manager in Virginia for President Grant. In his autobiography, Grant stated, "Since the close of the war, I have come to know Colonel Mosby personally and somewhat intimately. He is a different man entirely from what I supposed. He is able and thoroughly honest and truthful."
Mosby's friendship with Grant, and his work with those whom many Southerners considered the enemy, made Mosby a highly controversial figure in Virginia. He received death threats, his boyhood home was burned down, and at least one attempt was made to assassinate him. The danger contributed to the President's appointing him as U.S. consul to Hong Kong (1878–1885). Mosby then served as a lawyer in San Francisco with the Southern Pacific Railroad. Later he worked for the Department of the Interior, first enforcing federal fencing laws in Omaha, then evicting trespassers on government-owned land in Alabama. He also worked as assistant Attorney General in the Department of Justice (1904–10). He died in Washington, DC and is buried in Warrenton Cemetery.
Many years after the war, Mosby explained why, although he disapproved of slavery, he fought on the Confederate side. While he believed the South had seceded to protect slavery, he said, in a 1907 letter, that he had felt it was his patriotic duty to Virginia. "I am not ashamed of having fought on the side of slavery—a soldier fights for his country—right or wrong—he is not responsible for the political merits of the course he fights in ... The South was my country.