At 23 in 1847, Vaughn volunteered to fight in the
Mexican–American War. He was elected captain and marched to
Mexico City, but his regiment saw no military action. He left the military in July, 1848. In 1850, Vaughn and seventeen other Monroe County men set out for California gold. No fortunes were found, and John was back in
Tennessee by 1852. He built a hotel in the new railroad town of Sweetwater. In 1856 he was elected sheriff of Monroe County. During the
American Civil War, Vaughn raised Tennessee's first Confederate regiment and was with
Jefferson Davis in the final days of the war. His family was imprisoned by Union forces, and it was several years after the Civil War before he could safely return to Tennessee. Yet, he eventually was elected to the general assembly of his native Tennessee (1871–1873). Even before Tennessee had seceded, in early 1861 Vaughn recruited two units from Monroe County to support armed resistance to the Federal government. The recruits formed the 3rd Tennessee Infantry Regiment on May 29, and Vaughn was elected colonel. On June 18, Vaughn's men won a skirmish at New Creek near Maryland/West Virginia. On July 21, Vaughn's regiment traveled by train from the Shenandoah Valley to Manassas Junction. The regiment participated in breaking the Union right at the
First Battle of Bull Run. Vaughn's troops moved back to East Tennessee in 1862 and fought against Union factions in Scott County. In May, Vaughn's regiment patrolled the gaps in the northern Cumberland Mountains, winning battles in Tazewell in August and helping to regain control of
Cumberland Gap. In September, Vaughn was promoted to brigadier general. In December, General Vaughn's east Tennesseans traveled by train to Jackson, Mississippi. Vaughn's brigade held heights north of Vicksburg for the first four months of 1863. On May 17, Grant's forces sliced through the Confederate line at the
Battle of Big Black River Bridge forcing the surrender of two of Vaughn's regiments. The Confederates retreated into
Vicksburg where they eventually surrendered on July 4. Vaughn was paroled and in October began reassembling his troops. He won a skirmish against Union troops in Philadelphia, TN, and also combated marauders in his Monroe County. Part of
Longstreet's unsuccessful effort to take Knoxville in December, Vaughn was forced to retreat to upper East Tennessee. In late December, Vaughn was authorized to mount his brigade. In the summer of 1864, Vaughn's cavalry moved to the Shenandoah Valley. On June 5, the Union routed the Confederates at the
Battle of Piedmont. The Confederates under Grumble Jones were poorly deployed, and some of Vaughn's cavalry failed to engage. Gordon argues that Vaughn was with his dismounted troops on the Confederate left and not responsible for the inactive units. Following Jones' death at Piedmont, Vaughn led the remnants of the Confederate infantry across the Blue Ridge to Lynchburg, where it joined
John C. Breckinridge's division arriving from Richmond following Lee's victory at the
Battle of Cold Harbor, which in turn was shortly reinforced by
Jubal Early's division. After the
Battle of Lynchburg, Breckinridge and Early pursued General
David Hunter's retreating force to
Salem, Virginia and then marched north, for the Shenandoah Valley. In Early's invasion into Maryland that July, Vaughn's brigade was part of
John Echols' division, of Breckinridge's corps, and was present for the
Battle of Monocacy and
Fort Stevens. During the subsequent retreat into Virginia, Vaughn commanded
Robert Ransom Jr.'s cavalry division, while Ransom was ill. When the Army of the Valley was reinforced by troops under
Richard H. Anderson and
Fitzhugh Lee, Vaughn's mounted brigade was transferred from Echols' infantry division and joined the rest of Ransom's cavalry division, now under
Lunsford L. Lomax. It saw action at the
Third Battle of Winchester. In September, Vaughn returned to East Tennessee. He captured the railroad town of
Bull’s Gap and moved up to a forward position at a crossroads town called
Morristown. He was routed at the
Battle of Morristown in October by General
Alvan C. Gillem and was pushed back near Carter’s Station on the
Watauga River. Two weeks later under the command of General
John C. Breckinridge, Vaughn won a November skirmish against Gillem at the
Battle of Bull's Gap and pushed him back to
Strawberry Plains near
Knoxville. In April 1865, Vaughn and his troops were near Christanburg, Virginia, moving towards North Carolina after news of Lee's surrender. On April 19, Vaughn joined the Jefferson Davis escort in Charlotte. On May 10, Vaughn surrendered. Indicted for treason in Tennessee, in October, 1865, Vaughn moved his family to
Thomas County, Georgia. By 1870, Vaughn had returned to
Sweetwater, Tennessee and was elected to the
state general assembly (1871–1873). In 1874, he pleaded guilty to using bogus identities to defraud a widow's pension and was fined $1000. In 1874, Vaughn returned to southern Georgia. ==Personal life==