Serra was born Miquel Joseph Serra in Petra, Majorca, Spain. On November 14, 1730, he entered the Alcantarine Franciscans, a reform movement in the Order, and took the name "Junipero" in honor of Saint Juniper, who had also been a Franciscan and a companion of Saint Francis. For his proficiency in studies he was appointed lector of philosophy before his ordination to the Catholic priesthood. Later he received a doctorate in theology from the Lullian University in Palma de Mallorca, where he also occupied the Duns Scotus chair of philosophy until he joined the missionary College of San Fernando de Mexico in 1749.