Saint Martin was born in Lima, capital city of Peru, in the year 1579. His father was a Spanish knight and his mother a freed slave. He seems to have been neglected as a child, but he befriended a doctor who taught him the art of healing.

He was initially accepted as a servant at the Dominican Priory of Our Lady of the Rosary at Lima. Eventually admitted as a lay brother, he made profession in 1603. He worked with the sick and the poor, as well as taking care of animals, being known to have cured to most frightening of diseases and injuries (as much by prayer and intercession as by his medical skills).

He was taken to much prayer and penance. Having a particular devotion to the Blessed Eucharist, he would spend a long time in thanksgiving each time he received Holy Communion.

He died of fever on 3rd November 1639, and was canonised in 1962. His feast day is 3rd November.