A key figure in the Brazilian national school, Guarnieri served as a conductor, a member of the Academia Brasileira de Música, and Director of the São Paulo Conservatório.
Guarnieri's Italian father, Michele Guarneri?, a lover of classical music, named one of Camargo's brothers Rossine (a Portuguese misspelling of Rossini), and two others Verdi and Bellini.
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.
[3] 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.
[5] Shortly before his death in São Paulo in 1993, he was awarded the Gabriela Mistral Prize by the Organization of American States as the greatest contemporary composer of the Americas.