This required religious conversion and integration into the Spanish colonial economy – for the local Chumash people, the environmental changes wrought by the Mission's large herd of livestock, combined with epidemics and military force, meant that tribal members often had little choice but to join the mission system, resulting in a type of forced servitude.

Most probably under the direction of master stonemason José Antonio Ramiez (as estimated by historians), the work was performed by a labor force of Canalino people.

Some years later it was discovered that the concrete foundation of the church had begun to disintegrate while it was settling into the ground, thereby causing the towers to crack.

The larger reservoir, which was built in 1806 by the expedient of damming of Mission Canyon situated to the north within the existing Santa Barbara Botanic Garden, continued to serve as a functioning component of the city's water system until 1993.

Mission Santa Barbara was part of a broader plan by the Kingdom of Spain to protect its claim on Alta California against rival colonial powers (Russia and Great Britain).

[21] The main economic activity of the missions in the region that was occupied by the local Chumash tribe was animal husbandry and related products (hides and tallow).

[21] In 1818, two Argentine ships under the command of the French privateer, Hipólito Bouchard approached the coast and threatened the young town of Santa Barbara.

A military expedition, led by Captain Pablo de la Portilla, had been sent in pursuit of the Chumash "for the purpose of subjugating and restoring to their mission the neophytes of Santa Barbara who had fled to the tulares".

[29] After a seven-day long march from the Presidio, Captain de la Portilla and his division consisting of roughly 104 soldiers equipped with "caliber-4 cannon" arrived near Lake Tulares on June 9, 1824, and began negotiations for the surrender of the Indians (who were referred to as the rebels or fugitives); a process that took about six days.

The majority of those captured, including many women, children, and elders were marched back on a route leading across the Cuyama Valley and over the mountains southward towards the Santa Barbara Mission through San Roque Canyon on a journey (according to del Portilla's log) lasting from June 15 or 16, until their arrival on June 23 (with "straggling families" arriving over the course of subsequent days).

Although there are purportedly no records kept by the Franciscans which offer an explanation of the diminishing trend of the Chumash population, all of the California missions throughout their establishment experienced a mortality rate that exceeded their birthrate.

Bishop Francisco Garcia Diego y Moreno, OFM, established his cathedra at Mission Santa Barbara, making the chapel the pro-cathedral of the diocese until 1849.

Mission Santa Barbara includes a gift shop, a museum, a Franciscan Friary, and a retreat house.

Since the summer of 2017, the Mission has served as the Interprovincial Novitiate for the English Speaking Provinces of the Franciscan Friars (Observants).

'[34] The sources of the Library's collections can be traced to the 1760s with Fray Junipero Serra's plans for missions in Alta California.

[35] Beginning with the writings of Hubert Howe Bancroft, the Library has served as a center for historical study of the missions for more than a century.

The Mission archives contain one of the richest collections of colonial Franciscan music manuscripts known today, which remain closely guarded (most have not yet been subjected to scholarly analysis).