On 11 July 1762, Galvão was ordained a priest and transferred to St. Francis Friary in the city of São Paulo, where he continued his studies in theology and philosophy. In early 1766, around the completion of his studies, Galvão made a spiritual submission of himself as a "servant and slave" of the Blessed Mother, signing a document to this effect, dated 9 March, which he signed in his own blood. In 1768 he was appointed preacher, confessor and porter of the friary, an important post.