Secession and the Civil War deeply divided the Mexican Americans of Texas (Tejanos). Accusations of subversion and disloyalty before the war resulted in a reluctance by many of them to become involved in the conflict. Those who joined militia units in South Texas and on the frontier frequently did so out of a fear of being sent out of the state and away from their families. Some were able to avoid conscription by claiming to be residents of Mexico. Tejano frustrations during the Civil War are exemplified by the case of Capt. Adrián J. Vidal, who joined the Confederacy but deserted and enlisted in the Union Army, only to desert again and join the liberals in Mexico, where he was captured by the French and executed.
At least 2,500 Mexican Texans joined the Confederate Army. The most famous was Santos Benavides, who rose to command the Thirty-third Texas Cavalry as a colonel, and thus became the highest ranking Tejano to serve the Confederacy. Though it was ill equipped, frequently without food, and forced to march across vast expanses of South Texas and northern Mexico, the Thirty-third was never defeated in battle. Colonel Benavides, along with his two brothers, Refugio and Cristóbal, who both became captains in the regiment, compiled a brilliant record of border defense and were widely heralded as heroes throughout the Lone Star State. The Benavides brothers defeated a band of anti-Confederate revolutionaries commanded by Juan N. Cortina at Carrizo (Zapata) in May 1861 and on three separate occasions invaded northern Mexico in retaliation for Unionist-inspired guerilla raids into Texas. The Benavides brothers were also successful in driving off a small Union force that attacked Laredo in March 1864.
Many Tejanos who enlisted in the Confederate Army saw combat far from home. A few who joined Hood's Texas Brigade marched off to Virginia and fought in the battles of Gaines' Mill, Second Bull Run, Antietam, Fredericksburg, Gettysburg, the Wilderness, and Appomattox Court House. Thirty Tejanos who enlisted from San Antonio, Eagle Pass, and the Fort Clark area joined Trevanion T. Teel's artillery company, and thirty-one more joined Charles L. Pyron's company, both in John R. Baylor's Second Texas Mounted Rifles, which marched across the deserts of West Texas to secure the Mesilla valley. These units were later incorporated into Gen. Henry Hopkins Sibley's Confederate Army of New Mexico and fought bravely at the battle of Valverde.
Other Mexican Texans from San Antonio served in the Sixth Texas Infantry and fought in several of the eastern campaigns, including the battles of Chattanooga, Chickamauga, Atlanta, and at Franklin and Nashville in John Bell Hood's calamitous invasion of Tennessee. Two of the better known Tejanos in the regiment were Antonio Bustillos and Eugenio Navarro. Others who served the Confederacy included the younger Manuel Yturri, a Kentucky teacher and scholar, who rose to the rank of captain in the Third Texas Infantry; and Lt. Joseph de la Garza, also from San Antonio, who died at Mansfield, Louisiana, in 1864 during the Red River Campaign. More than 300 Texas Mexicans from Refugio and Bexar counties joined the Eighth Texas Infantry. Two companies commanded by Joseph M. Peñaloza and José Ángel Navarro were almost entirely Tejano.
Other Texas Mexicans, resentful of growing non-Hispanic political dominance of their communities, enlisted in federal blue. Many joined the Union Army for the bounty money offered upon enlistment, but some enlisted because they opposed slavery or to satisfy grudges against landowners, attorneys, and politicians who had used the American legal system to take valuable land from Tejanos during the preceding decade. The federal Second Texas Cavalry, commanded by Col. John L. Haynes, a resident of Rio Grande City, was composed almost entirely of Tejanos and Mexican nationals recruited from the small villages along the banks of the Rio Grande. The regiment, which suffered an exceptionally high desertion rate, fought in the Rio Grande valley and later in Louisiana. Company commanders included George Treviño, Clemente Zapata, Cesario Falcón, and Mónico de Abrego. A number of Tejanos, acting as Union consorts, were actively engaged in the Nueces Strip. The most famous of the Union guerillas were Cecilio Balerio and his son Juan, who fought a bloody skirmish with Confederates at Los Patricios, fifty miles southwest of Banquete, on March 13, 1864.