Alvarado was born in
Monterey,
Alta California, to Jose Francisco Alvarado and María Josefa Vallejo. His grandfather Juan Bautista Alvarado accompanied
Gaspar de Portolá as an enlisted man in the Spanish Army in 1769. His father died a few months after his birth and his mother remarried three years later, leaving Juan Bautista in the care of his grandparents on the Vallejo side, where he and
Mariano Guadalupe Vallejo grew up together. They were both taught by
William Edward Petty Hartnell, an English merchant living in Monterey. In 1827, eighteen-year-old Alvarado was hired as secretary to the
Diputación de Alta California (legislature). In 1829 he was briefly arrested along with Vallejo and
José Castro by soldiers involved in the military revolt led by
Joaquín Solis. In 1831 he built a house in Monterey for his mistress, Juliana Francisca Ramona y Castillo, whom he called "Raymunda", to live in. It's possible the home was for her sister, Maria Reymunda Castillo. Over the years, the pair had at least two illegitimate daughters whom he recognized: Estefana del Rosario (born 1834) and Maria Francisca de la Asencion (born 1836). They may have had several more that he did not recognize, but they never married. During this period Alvarado began drinking heavily.
Supports secularization Alvarado supported
secularization of the
Spanish missions in California. He was appointed by
José María de Echeandía to oversee the turn over of
Mission San Miguel, even though Echeandía was no longer governor. The new governor
Manuel Victoria rescinded the order and sought to have Alvarado and Castro arrested. The pair fled and were hidden by their old friend Vallejo, who had become
adjutant at the
Presidio of San Francisco. However, Victoria was unpopular and Echeandía overthrew his rule and replaced him with
Pío de Jesús Pico near the end of 1831. Secularization of the missions resumed in 1833. In 1834 Alvarado was elected to the
Diputación de Alta California as a delegate and appointed customs inspector in Monterey. Governor
José Figueroa granted
Rancho El Sur, two square leagues of land, or about , south of Monterey, to Alvarado on October 30, 1834.
Independence movement in
Los Angeles. Alvarado's flag inspired the red star in the
Bear Flag of California. After Figueroa's death in September 1835, Nicolás Gutiérrez was appointed as interim governor in January 1836. He was replaced by
Mariano Chico in April, but Chico was unpopular. His intelligence agents told him that another Californio revolt was brewing, hence he fled to
Mexico, claiming he planned to gather troops against the independent Californios. Instead, Mexico reprimanded him for abandoning his post. Gutierrez, the military
commandant, re-assumed the governorship, but like the Mexican governors before him, the Californios forced him to flee. As senior members of the Diputación de Alta California, Alvarado and Castro, with political support from Vallejo and backing from a group of Tennesseans led by Capt.
Isaac Graham, staged a revolt in November 1836 and forced Gutierrez out of the country. Alvarado's Californio coup wrote a constitution and adopted a
new flag—a single red star on a white background, but neither were used after Alvarado made peace with Mexico in October of 1836. ==Governor Alvarado==