In 1832, de la Garza became Mayor of San Antonio. That year he signed the articles from the Convention of 1832. Probably at the beginning of 1834 he bought the San Francisco de la Espada Mission. This purchase, however, was deemed illegal by some residents, leading to a rejection of him. This rejection was further strengthened when during the Texas Revolution (1835-1836), some Texas residents thought that his family defended the idea that Texas should remain Mexican (Texas was a province of Mexico previous to the Revolution).