De Salazar wrote almost only religious polyphony in Latin, except for the villancicos, which are in Spanish. Most of these are lost as nothing was printed, even though some of his many Motets were still sung in the late 19th century at Zamora. He left music for almost the entire liturgical needs of the cathedral: psalms, hymns, numerous motets and above all the Office of the Dead, which he wrote not in one go but part by part, yet ending up with a consistant service.
De Salazar left his native environment as a young adult, and, after several appointments elsewhere in Castille, became Maestro de capilla of the cathedral in Zamora in 1668, where he stayed till his death there. Such a long term of office was unusual — most colleagues sought better paid appointments — so he is believed to have been happy there and not very ambitious; he was succeeded by his own pupil Tomé Alonso Cobaleda.