He joined the College of San Fernando de Mexico in 1804 and became a missionary to the California Native Americans in August 1805.
From 19 July to 14 August 1806, Zalvidea accompanied an expedition from Santa Barbara east and then south to San Gabriel in search of new mission sites, meanwhile baptizing many dying people.
[5] Zalvidea served at Mission San Gabriel Arcángel beginning in 1826, where he was a major formative influence, responsible for much of its economic development.
On the other hand, contemporary writer Hugo Reid criticizes his treatment of the natives, describing him as "severe" and "most cruel", and as making unusually heavy use of flogging, as well as other notably punitive practices.
The penalty inflicted was, shaving the head, flogging for fifteen subsequent days, iron on the feet for three months, and having to appear every Sunday in church, on the steps leading up to the altar, with a hideous painted wooden child in her arms.