Mexican era (1834-1846):
- After the Mexican government secularized the mission in 1834, the mission lands were divided and granted to private individuals, leading to the dispersal of Indigenous Chumash people who had been associated with the mission.
- The mission buildings began to deteriorate due to lack of maintenance and abandonment.
American era (1846-present):
- Following the United States' acquisition of California after the Mexican-American War, many of the mission's former lands were recovered by the Catholic Church through legal challenges and purchases.
- In 1853, Mission Santa Barbara became a parish church and an active Franciscan friary again, as Catholic religious orders were allowed to return to California.
- Restoration efforts to preserve and restore the mission's buildings began in the late 19th century, and significant reconstruction occurred throughout the 20th century to bring the mission as close as possible to its original appearance.
- Today, Mission Santa Barbara stands as a historical landmark and parish church and is open to the public for visits, tours, and events.
It operates as a functioning parish within the Archdiocese of Los Angeles and also preserves its historical significance through museum exhibits and educational programs.