His birth date is unknown but he was baptized as Francisco Bartolomé Sanz Celma in the church of Calanda de Ebro, Aragon on 4 April 1640 later adopting the first name "Gaspar".

Sanz learned to play guitar while studying under Lelio Colista and was influenced by the music of the Italian guitarists Foscarini, Granata, and Corbetta.

When Sanz returned to Spain he was appointed instructor of guitar to Don Juan (John of Austria), the only recognized natural-born son of King Philip IV and María Calderón, a noted actress of the day.

In addition to his musical skills, Gaspar Sanz was noted in his day for his literary works as a poet and writer, and was the author of some poems and two books now largely forgotten.

For example, there is a "Zarabanda francesa" (french sarabande) which includes the sequence CIFI+H2+G2K2IFCM2N2CAIC, which means: Gaspar Sanz strongly influenced some twentieth-century composers.