Whitfield was promoted to brigadier general in May 1863. The brigade returned to Mississippi and occupied a position generally on the periphery of action during the Vicksburg campaign. Whitfield's health deteriorated, and Sul Ross of the Sixth Texas was appointed brigade commander. Because Ross was at that time on detached service with his regiment, command of the Texas Brigade temporarily went, on October 29, 1863, to Col. Hinche P. Mabryqv of the Third Texas Cavalry.qv Ross took formal command in mid-December 1863 and was promoted to general a few days later. The Texans spent most of the next five months operating against Union troops in the Yazoo River valley before being ordered to Georgia.
During the ensuing Atlanta campaign, the Texans spent 112 days under fire and participated in eighty-six engagements. They began the general fighting (May 25-June 5) at New Hope Church near Dallas, Georgia, but attrition had so reduced their ranks that the Texas regiments were overrun by the superior forces of Edward M. McCook and Hugh Judson Kilpatrick later that summer. After the fall of Atlanta the Texans marched with John Bell Hood'sqv troops into Tennessee. Throughout the disastrous campaigns of November and December 1864, they served as vanguards and rear guards, raided Union supply trains, and battled federal cavalry. In the withdrawal from Nashville they were one of Gen. Nathan Bedford Forrest's two brigades covering the Confederate retreat. By then dissension was rife in the brigade, and desertions occurred frequently. General Ross returned on leave to Texas on March 13, 1865, probably in an attempt to recruit replacements for the depleted ranks. Col. Dudley W. Jonesqv of the Ninth Texas was in command of the brigade at its surrender on May 4, 1865, at Jackson, Mississippi.
Ross's Brigade, one of the most famous Texas military units of the Civil War,qv was also one of the most active. It was not, however, distinguished for its discipline. Its members were described as "rollicking, rascally, [and] brave" and appreciated for their dependability. Gen. Stephen D. Lee called the Texans the "most reliable" troops under his command. In 1875 survivors of the unit organized the Ross Brigade Association.

