The unit traveled to Shreveport, Louisiana, in July 1862 where they remained until 18 July 1862. The soldiers then traveled northward and arrived in Austin, Arkansas, on 3 September 1862. By late September the unit was dismounted (i.e. the unit was converted to infantry). The 28th Texas Cavalry was dismounted because of a surplus of cavalry units in Arkansas and because of a lack of forage for the horses. The men refused to call themselves "infantry" instead preferring the term "dismounted cavalry" as though it were a temporary condition. Much to the disappointment of the men, the 28th Texas was never remounted. During this time period, companies L and M were removed from the unit. Company L remained mounted and became part of Lt. Colonel Charles L. Morgan's Texas Cavalry Regiment. Company M became part of the 14th Texas Infantry, a unit that often served in the same brigade as the 28th Texas.

In September, the unit was brigaded with the 11th Texas Infantry, the 14th Texas Infantry, the 15th Texas Infantry, and the 6th Texas Cavalry Battalion (dismounted). Colonel Horace Randal became commander of this brigade, and Lt. Colonel Eli H. Baxter, Jr. became commander of the 28th Texas.

The unit spent the entire war in the Trans-Mississippi and campaigned extensively in Arkansas and Louisiana. By December 1862 the unit became part of Major General John G. Walker's Division. This division was comprised of three brigades made up entirely of Texas units. The major campaigns that the 28th Texas Cavalry (dismounted) served in were the following:

Attempt to Relieve Vicksburg, Mississippi (November 1862 - July 1863). The unit was held in reserve at the battle of Milliken's Bend. Walker's Division traveled about 1,600 miles during this campaign.

Repulse of Major General William B. Franklin's army (Fall of 1863). Randal's brigade (including the 28th Texas) went on an expedition from Alexandria, Louisiana, toward Harrisonburg, Louisiana. The men were probably involved in light skirmishing and lost two men captured. Involved in a skirmish near Moundville, Louisiana, on 24 October 1863. Walker's Division then spent much of November bombarding enemy transports on the Mississippi River.

Red River Campaign (March-April 1864). Portions of Company D and Company I were stationed at Fort DeRussy, Louisiana, when Union forces started their advance up the Red River. Twenty-three soldiers, out of a detachment of thirty-five, escaped capture at the fort. The 28th Texas fought at the battles of Mansfield (April 8th) and Pleasant Hill (April 9th). Casualties for the 28th Texas at these two battles were:

Mansfield: 4 killed, 17 wounded

Pleasant Hill: 9 killed, 44 wounded, 2 missing

The March to Arkansas (April 1864). With little rest, the men of Walker's Division marched into Arkansas in an attempt to destroy a Federal army under the command of Major General Frederick Steele. Along with Confederate troops from Missouri and Arkansas, Walker's Division attacked Steele's army near Jenkins' Ferry on 30 April 1864. The 28th Texas lost 20 killed and 40 wounded at this battle. Horace Randal was mortally wounded at this battle and died on 2 May 1864.

The Last Year (May 1864-May 1865). Further marches took place in Arkansas and Louisiana in this last year, but the unit saw no fighting. In March 1865, the division returned to Texas where they disbanded in May 1865.

For further information about the men who comprised the 28th, their campaigns, soldier life in the Trans-Mississippi, the two mutinies of the 28th, and many other interesting topics please see the following book: