Miquel Josep Serra was born in a stone farmhouse in Petra, Majorca, the son of poor farmers. He took the name Junípero — after one of Francis of Assisi's first companions — when he entered the Franciscans at seventeen. By thirty he was a professor of philosophy with a doctorate in theology; he could have remained an honored academic in Spain for the rest of his life.
In 1749, aged thirty-five, he volunteered for the New World missions and crossed to Mexico. On the walk inland from Veracruz to Mexico City an insect bite became infected; the leg ulcer never healed and gave him pain for the rest of his life. He spent eighteen years among the Pamé people in the Sierra Gorda before being sent north into Alta California.
Between 1769 and his death in 1784 he founded nine of California's twenty-one Spanish missions: San Diego, San Carlos (Carmel), San Antonio, San Gabriel, San Luis Obispo, San Juan Capistrano, San Francisco de Asís (Dolores), Santa Clara, and San Buenaventura. He walked thousands of miles on his ulcerated leg, baptized perhaps six thousand Indigenous Californians, and confirmed five thousand more under a special apostolic faculty granted because no bishop yet existed in California.
His missions, and the system he founded, are today the subject of intense and legitimate historical debate over their consequences for Indigenous Californian peoples — disease, forced labor, and cultural disruption among them. The Church's case for his sanctity rests on his personal holiness, his repeated written defense of Indigenous people against Spanish soldiers and colonial governors (his 1773 Representación to the Viceroy is a foundational document of Indigenous-rights advocacy in the Americas), and the witness of contemporaries who knew him as a man of penance, prayer, and personal poverty.