Joaquín Leal, rancher, was born in 1746 in the Villa de San Fernando (San Antonio) to Bernardo Leal and Lenore Delgado, Canary Islanders among the villa's original founders. His grandfather, Juan Leal Goraz, had, by royal decree, led the colony and was the first alcalde mayor of San Fernando. After the founding of San Fernando, the land grants given to each of the colonists at his arrival became farms and cattle ranches extending for miles in all directions. By virtue of their land titles, landowners took a place of social prominence. Leal's sizable ranch, known as Santa Rita de las Islitas, provided him with thousands of acres of productive ranchland. In 1770 his wealth and social standing were strengthened with his marriage to Ana María de Arocha, the granddaughter of colonial leader Francisco de Arocha and subsequent heiress to much of the Arocha land. Her father, Símon de Arocha, owned property adjacent to Leal's, so the Leal-Arocha union in essence expanded the Leal cattle empire. Leal's political influence arose from his position on the local council as regidor de cano and through family ties to the Bexar military. By 1798 Leal had fathered at least eighteen children, but only five of these lived past infancy.
In the spring of 1813 an army of freebooters, known as the Gutiérrez-Magee expedition, successfully routed the Spanish military from Coahuila and Texas. By April the expedition had made its headquarters at San Antonio de Valero Mission with the cooperation of the San Fernando military, who perceived an end to Spanish rule. To ensure their safety and to retain their property and social standing under the new rule, a large segment of the population, including the Leal family, aligned themselves with their apparent conquerors. By August of that year Spanish general Joaquín de Arredondo mounted a large-scale response to the insurgent takeover, leading more than 2,000 troops in a defeat of the rebel army. Only a handful of the insurgents survived the siege.
Branded as traitors to the crown, many families left their homes and fled toward the Sabine River and the safety of Louisiana. Before reaching the Trinity River, a group of republicans, including the Leal, Arocha, and Delgado families, was apprehended by Elizondo's troops. Leal and the heads of the other families were bound and led on a forced march to Fort Trinidad to stand before Elizondo, who considered his captives a great prize and unworthy of mercy and so condemned the men to instant death. They were led before their weeping families, where they were shot and denied burial. Their houses, cattle, and properties were confiscated. The now-destitute female members of their families, including Leal's daughters, Consolación Leal de Garza and Juana Leal de Tarín (wife of Vizente Tarín), were imprisoned under the harshest of conditions for many weeks. By 1814 clemency was offered to many of the families, but only a small measure of their property was ever restored to them. In 1819, six years after his execution, Leal's skeletal remains were recovered from Trinidad and given a Christian burial in January in the campo santo of the San Fernando Church (now San Fernando Cathedral).