Jose Toribio Medina was born in Santiago, Chile. He was the eldest son of José del Pilar Medina y Valderrama and Mariana Zavala y Almeida, a woman of
 His father was a lawyer, and he was constantly traveling due to his position as a magistrate. For this reason, Medina spent his childhood in different cities like Santiago, Talca, and Valparaiso. At the age of thirteen, he returned to Santiago to support his father who had lost the use of his legs. Later on, Medina joined the National Institute under the direction of the great historian Diego Barros Arana. Then he studied law at the University of Chile, graduating as a lawyer on March 26, 1873.
 His first publication, when a very young man, was a metrical translation of
Henry Wadsworth Longfellow's
Evangeline. At twenty-two he was appointed the secretary to the legation at
Lima, Peru. After his return, he published a history of
Chilean literature (1878), and a work upon the aboriginal tribes (1884).
In this latter year, he was appointed the secretary of legation in
Spain, and availed himself of the opportunity of examining the treasures of the old Spanish libraries. These researches, repeated on subsequent visits to Spain, and also to
England, enriched him with a mass of historical and bibliographical material. Among his publications may be mentioned the
Biblioteca hispano-americana, a remarkable catalogue of unedited documents relating to the Spanish discovery and colonization of Chile, including a number of articles from Martín Fernández de Navarette. Volumes II and III of this collection focus on Ferdinand Magellan, from where the recorded history of Chile starts; the
Biblioteca hispano-chilena, a similar work, commenced in 1897; the standard and magnificent history of printing in the
La Plata countries (1892); comprehensive works on the
Inquisition in Chile,
Peru and the
Philippines; and the standard treatise on South American medals (1899).