 He studied piano with Ernani Braga and and composition with at the Conservatório Dramático e Musical de São Paulo.In 1938, a fellowship from the Council of Artistic Orientation allowed him to travel to Paris, where he studied composition and aesthetics with Charles Koechlin and conducting with François Ruhlmann .Some of his compositions received important prizes in the United States in the 1940s, giving Guarnieri the opportunity of conducting them in New York, Boston, Los Angeles and Chicago.