He grew up in a peasant who received deep experiences that mark his later life with simplicity and resilience of spirit, as well as the radicalism of their unconditional dedication to priestly ministry. In 1860 entered the College of St. Joseph of Marinilla (Antioquia), where he studied mathematics, geography, history and Spanish. Approves with excellent results his studies and decided to enter the seminary in Medellín to become a priest.

On February 3, 1869, at 24 years old, entered the newly opened seminary in Medellin, where he prepared very hard for the priesthood. On July 14, 1872 was ordained a priest. His pastoral work was developed especially among the peasants, the poor and humble.

He died in Angostura, Colombia, on July 13, 1926, at the age of eighty, soon to be eighty-one, and after nearly forty-three years of dedication to the parish pastoral Angostura.

On October 10, 1980, the Congregation for the Causes of Saints accepts and begins the process of beatification of Father Mariano. On March 3, 1990, are proclaimed her heroic virtues and begins to hold the title of Venerable. Later, on March 26, 1999, Pope John Paul II attends the ceremony of reading and approval of decrees recognizing miracles and signs for a favor done by the intercession of Father Mariano.