He carried out his ecclesiastic studies in the Seminary of Lugo and after studying Philosophy, he went on studying Theology and Civil Law in Santiago, entering the Dominican Order in 1842.
In 1844, he was ordained as a priest in Cádiz and moved to Manila, taking in charge of the chair in Humanities at the University of Santo Tomas. One year later, he joined the mission in Tung-King and was nominated as bishop of Vi-Koang in 1849.
Fray José Mª Díaz Sanjurjo was arrested and executed in 1857, which was an excuse for the French military intervention in Cochinchina, which was also supported by Spain (1858-1862).
There is a book about the campaign in Cochinchina.