Young Casella from Turin completed his musical education in Paris where he studied the piano with the famous virtuoso Louis Diémer and composition with Gabriel Fauré, becoming a highly regarded pianist (he formed, among other things, a group with Bonucci and Poltronieri which was to become very famous: the Trio Italiano).
He was one of the principle representatives of the so-called Generazione dell'ottanta along with Alfano, Malipiero, Pizzetti
Musicologist and teacher, he supervised the editing of many works for piano and contributed to the rediscovery of Vivaldi.
Among his works, the most performed are his divertissements on the composers of the past, such as the famous Scarlattiana, Divertimento su musiche di Domenico Scarlatti per pianoforte e piccola orchestra of 1926
, the Paganiniana
, divertimento per orchestra op.65 del 1942, various concertos, symphonies and works for piano.