José Menchaca was the son of Ignacia (Núñez Morillo) and Luis Antonio Menchaca. He followed in his father's military footsteps and became an alferez (ensign) in the Bexar presidio company in 1771. Upon the retirement of Cristóval de Córdova in 1775 Menchaca was named first lieutenant of cavalry. After Governor Juan María Vicencio de Ripperdá founded a fort on the Arroyo de Cíbolo (now Cibolo Creek), José was placed in charge of twenty men at the installation. Their job was to patrol between San Antonio and La Bahía (Goliad) and protect the ranches from Indian depredations. Menchaca was given command of the Bexar presidio during Governor Domingo Cabello y Robles's nine-month absence in 1780. Upon returning to the capital, Cabello arrested Menchaca and sent him "in disgrace" to the presidio at San Juan Bautista, an action apparently related to the governor's feud with the Menchaca family. Nonetheless, Menchaca was placed in command of Presidio Agua Verde in 1783 and saw duty in Coahuila as a captain until his retirement in 1801. According to his military record, filed July 4, 1811, Menchaca was a twenty-nine-year veteran of the Royal Service and had seen action all along the northern frontier. He married María Encarnación Rodríguez in 1800 and returned to Bexar. Four years later he sold the building that came to be known as the Spanish Governor's Palace to Ignacio Pérez; he disposed of his interest in his deceased father's Rancho de San Francisco to Vicente Micheli that same year.
At the outbreak of the Mexican War of Independence Menchaca's support was solicited by the insurgents, and he joined them in the early going. As their prospects faded he embraced the Royalist cause and was instrumental in the capture of Hidalgo at the Wells of Baján. He set out to clear his name at Bexar but apparently fell into disfavor with the commandant general, Nemecio Salcedo. Menchaca fled and found refuge at Revilla (now Guerrero, Tamaulipas) with one of Hidalgo's supporters, José Bernardo Gutiérrez de Lara. Together they left Revilla in July 1811 and headed for the United States, where Gutiérrez hoped to enlist aid for the revolutionary cause. On their arrival at Natchitoches, Gutiérrez instructed Menchaca to return to Bexar with a body of American volunteers that had assembled, to seize the capital of Texas, and then to send credentials as a representative of the new government to Gutiérrez, who would be awaiting word of the conquest in Washington, D.C. Menchaca led 300 American volunteers against Nacogdoches in October 1811, but when they crossed the Sabine River and encountered Spanish troops, he apparently had second thoughts and again defected to the Royalists. Governor Manuel de Salcedo granted him a pardon but was overruled by his uncle, the commandant general. Menchaca was tried at Bexar for sedition, found guilty, and sent to prison in Chihuahua. According to Antonio Menchaca's Memoirs, José died there in 1820, a victim of the social upheavals that attended Mexico's struggle for independence. He has been much confused with his kinsman, Miguel Menchaca, who died in the battle of Medina.