After transporting his army by train to Chattanooga, Tennessee, Bragg worked with General Edmund Kirby Smith during a Confederate invasion of Kentucky in August 1862. In October Bragg engaged the forces of General Don Carlos Buell at the Battle of Perryville. While his troops succeeded in striking a blow against a portion of Buell’s army, Bragg did not press the victory and instead made the controversial decision to withdraw to Knoxville. Bragg would face a setback at the Battle of Stones River in December 1862 and January 1863, when Union forces under General William Rosecrans repulsed repeated Confederate offensives. During this time Bragg’s leadership came under considerable scrutiny, and many of his subordinates began to call for his replacement.
During the Tullahoma Campaign in the summer of 1863, Bragg evacuated Chattanooga and withdrew to Georgia with Rosecrans in pursuit. While he fell back, Bragg was able to take on significant reinforcements to his Army of Tennessee, and in September 1863 he counterattacked during the Battle of Chickamauga. With the help of General James Longstreet’s corps, Bragg launched a successful offensive that collapsed the Union left flank and nearly destroyed Rosecrans’s army.
The Battle of Chickamauga proved to be the most significant Confederate victory in the Western Theater, resulting in more than 30,000 casualties. But despite his clear advantage, Bragg once again declined to capitalize on his victory and instead allowed the Union Army to retreat to Chattanooga. Bragg then laid siege to the city, but was dealt a decisive defeat by General Ulysses S. Grant during the Battles of Lookout Mountain and Missionary Ridge in November 1863. Bragg withdrew to Georgia that same month, still under bitter criticism from his subordinate officers. He offered his resignation to Davis shortly thereafter and was replaced by General Joseph E. Johnston in December 1863.