As a teenager, Mariano, his nephew Juan Bautista Alvarado (1809–1882), and José Castro (1808–1860) received special instruction from Governor Pablo Vicente de Solá.

Vallejo was serving as the personal secretary to the new Governor of California, Luis Argüello, when news of Mexico's independence reached Monterey.

He was promoted to alférez (equal to a modern army second lieutenant), and in 1829, Vallejo led a group of soldiers against the Miwoks, under chief Estanislao.

After a three-day battle, Vallejo's troops forced the Miwok to flee to Mission San José, seeking refuge with the padres.

Vallejo transferred most of the soldiers from San Francisco to Sonoma, and began construction of his two-story Casa Grande adobe on the town plaza.

[citation needed] Governor Figueroa died in September 1835, and was replaced by Nicolás Gutiérrez, who was unpopular with the Californio population, resulting in an uprising headed by Juan Alvarado the next year.

[citation needed] In 1840, Isaac Graham allegedly began agitating for a Texas-style revolution in California, in March issuing a notice for a planned horse race that was loosely construed into being a plot for revolt.

Alvarado notified Vallejo of the situation, and in April the Californian military began arresting American and English immigrants, eventually detaining about 100 in the Presidio of Monterey.

Under pressure from British and American diplomats, President Anastasio Bustamante released the remaining prisoners and began a court martial against Castro.

After several months of negotiations and delays by the Mexican authorities and Governor Alvarado (who feared his uncle was plotting to overthrow him), John Sutter purchased the fort.

This economic and military setback confirmed Vallejo's belief that it would be better if California was no longer ruled from Mexico City[citation needed].

However, after the Graham affair, Vallejo was reluctant to deport another group of Americans[citation needed], especially those with skills useful for colonizing the northern frontier.

In 1842, the Federal Government replaced Vallejo and his nephew Alvarado with Manuel Micheltorena as both civil and military Governor of Alta California.

In the early morning of June 14, 1846,[8] Mariano Guadalupe Vallejo was taken prisoner by a ragtag band of Americans, led by William B. Ide, who had decided to emulate the Texans by revolting against California's Mexican government.

Instead of resisting, Vallejo, who favored the American takeover of California, invited the rebels inside his quarters in the Casa Grande for a meal and drinks.

Although Vallejo was sympathetic to the advent of American rule,[9] he deemed the perpetrators of the Bear Flag Revolt to be mere lowlife rabble.

Ill-advisedly, however, as some say, or dominated by a desire to rule without let or hindrance, as others say, they placed themselves under the shelter of a flag that pictured a bear, an animal that we took as the emblem of rapine and force.

This mistake was the cause of all the trouble, for when the Californians saw parties of men running over their plains and forests under the 'Bear Flag,' they thought that they were dealing with robbers and took the steps they thought most effective for the protection of their lives and property.Vallejo, his French secretary Victor Prudon, his brother Salvador Vallejo, and their brother-in-law Jacob P. Leese were taken as prisoners to John C. Frémont's camp in the Central Valley.

Once the United States defeated Mexico in the war, Vallejo proved his allegiance to his new country by persuading wealthy Californios to accept American rule.

The offer was accepted by the new state legislature and signed into law by Governor John McDougall, convening in Vallejo, as the new city was named, for the first time in 1851.

[11] General Vallejo is in the history books as a person who "fought for the rights of the Native Americans", but also one who would "go out on raids into Indian territory to bring back new workers".

Jose Manuel Salvador Vallejo (1813–1876), the General's younger brother, received his commission in the Mexican army in 1835, and was appointed Captain of militia at Sonoma in 1836.

Major Vallejo organized the 1st Battalion of Native Cavalry, California Volunteers, and he served as far east as Arizona, but did not have a battlefield role in the Civil War.

María Paula Rosalia Vallejo (1811–1889), the General's sister, married Jacob P. Leese grantee of Rancho Huichica and other properties.

[18] By the time of his death on January 18, 1890, Vallejo led a modest lifestyle on the last vestige of his once vast landholdings at his Lachryma Montis home in Sonoma, California.

[23] Actor George J. Lewis was cast as General Vallejo in the 1956 episode "The Bear Flag," on the syndicated television anthology series Death Valley Days, hosted by Stanley Andrews.