Gaspar Cassadó was born in Barcelona on the 30th of September 1897, and it was in that city where he began to study music at the early age of 5. In 1907 he moved to Paris with his father, the musician Joaquim Cassadó. In Paris he met and studied with Pablo Casals. He there studied harmony with Ravel and Falla. His studies with Casals had a profound effect on him both technically and musically, that marked the rest of his life. One of the great cellists of the 20th century performed on all seven continents. He was very interested in contemporary music giving many work premiers of works by authors such as Morera, Honegger, Hindemith, Castelnuovo- Tedesco, Martinu, Delius, Dallapiccola, Tansman, Pfitzner, Halftner, Khachaturian and many others.
In the Late 50's he formed duo with Alicia de Larrocha and they performed frequently in Spain and Europe. He taught in Musica en Compostela and later in the Academia Musicale Chigiana in Siena. He performed with many of the great masters of the 20th century, Oistrakh, Rostropovich and Menuhin. He was juror of many international cello competitions. Radu Aldulesco, Marçal Cervera and Elias Arizcuren are among the few of his outstanding students. As a composer, he made many transcriptions for cello, as well as chamber music and a few pieces for solo piano.
He married the japanese pianist Chieko Hara. He died in Madrid the 24th of December 1966.