His grandfather Juan Bautista Alvarado accompanied Gaspar de Portolá as an enlisted man in the Spanish Army in 1769.

In 1829 he was briefly arrested along with Vallejo and José Castro by soldiers involved in the military revolt led by Joaquín Solis.

However, Victoria was unpopular and Echeandía overthrew his rule and replaced him with Pío de Jesús Pico near the end of 1831.

Governor José Figueroa granted Rancho El Sur, two square leagues of land, or about 9,000 acres (3,600 ha), south of Monterey, to Alvarado on October 30, 1834.

[6] As senior members of the legislature, Alvarado and Castro, with political support from Vallejo and backing from a group of Tennesseans led by Capt.

Mexico reneged on the agreement, however, and appointed Carlos Antonio Carrillo, who was very popular among the southerners, governor on December 6, 1837.

Alvarado married Doña Martina Castro on August 24, 1839, in Santa Clara, but did not attend his own wedding having his half-brother, Jose Antonio Estrada, stand in for him.

In April 1840 a report of a planned revolt against Alvarado by a group of foreigners, led by former ally Isaac Graham, caused the governor to order their arrest and deportation to Mexico City for trial.

Also in 1841, political leaders in the United States were declaring their doctrine of Manifest Destiny, and Californios grew increasingly concerned over their intentions.

In response, Mexican president Antonio López de Santa Anna sent Brigadier General Manuel Micheltorena and 300 men to California in January 1842.

In October, before Micheltorena reached Monterey, American Commodore Thomas ap Catesby Jones mistakenly thought that war had broken out between the US and Mexico.

This turned out to backfire on him, as on November 14, 1844, a group of Californios led by Manuel Castro revolted against Mexican authority.

The rebels won the Battle of Providencia in February 1845 at the Los Angeles River and Micheltorena and his troops left California.

He prepared to move to Mexico City, but Pico declined funding for the transfer, and relations between northern and southern California deteriorated further.

Afraid of foreign aggression, Castro assembled his militia, with Alvarado second in command, but Frémont went north to Oregon instead.

An unstable political situation in Mexico strained relations among the Californios and it seemed that civil war would break out between north and south.

After the war, Alvarado was offered the governorship but declined, instead retiring to his wife Martina's family estate at Rancho San Pablo in 1848.