He worked as a shepherd until age 24, when in 1649, he began to make his way to Guatemala, hoping to connect with a relative engaged in government service there. By the time he reached Havana, Cuba he was out of money. After working there to earn more, he got to Guatemala City the following year.
When he arrived he was so destitute that he joined the bread line which the Franciscans had established. He fell sick almost immediately but was able to recover his health.
He very much wanted to become a priest and soon enrolled in the local Jesuit college (Jesuit College of San Borgia) in hopes of studying for the priesthood. No matter how hard he tried, however, he could not master the material, and thus withdrew from the school.
Unable to take holy orders, he became a tertiary in the convent of Costa Rica in Antigua Guatemala, and took the name "Peter of Saint Joseph". He visited hospitals, jails, the unemployed, and the young. Three years later, he opened Our Lady of Bethlehem, a hospital for the convalescent poor. Soon after there was a shelter for the homeless, schools for the poor, an oratory, and an inn for priests. He was imitated by other tertiaries and Hermano Pedro soon wrote up a rule, which was adopted by the women who were involved in teaching the children. This led to the formation of a new religious order: la Orden de los Bethlemitas y de las Bethlemitas, subsequently recognized and approved by the Holy See.
He died in Antigua Guatemala at the age of 41. He left behind devotional writings.
His tomb is in the San Francisco Church, in Antigua, Guatemala.
He is sometimes credited with originating the Christmas Eve posadas procession in which people representing Mary and Joseph seek a night's lodging from their neighbors. The custom soon spread to Mexico and other Central American countries.