Mariano Guadalupe Vallejo (7 July 1808 - 12 January 1890) was born at Monterey, California, entered the Monterey Presidial Academy in 1823. Appointed Secretary to the Governor of California in 1825, he later served as Commander of the Presidio of San Francisco, and in 1836 was appointed Commandante General and Director of Colonization of the Northern Frontier, the highest military command in northern California. That appointment ended during the Bear Flag Revolt, when Vallejo supported the Bear Flagers. General Vallejo, in spite of substantial losses suffered as a result of that revolution, and his imprisonment during the revolt by the leaders of the California Republic, chose to remain in his home State and support separation from Mexico and annexation by the United States. An influential member of the State's Constitutional Convention, he was elected a member of the first State Senate (1850).

In 1844, he was deeded title to Rancho Soscol, which included what is now the town of Petaluma. In 1850, he offered to donate a large portion of that land to the new state on which to build a capitol city and also offered to pay for a considerable amount of construction. The offer was accepted by the new legislature and they convened there for the first time in 1851. However, construction had lagged, and they were confronted with inadequate, leaky buildings and a soggy location, and within a year had moved the capitol to Sacramento. Vallejo's large adobe home is now part of the Petaluma Adobe State Historic Park and a National Historic Landmark.

He continued to devote his energies to the development of California for the remainder of his life. General Vallejo died at Sonoma, California.

The submarine USS Mariano G. Vallejo was also named in his honor.