Fernandez studied at the Instituto Nacional de Musica with Francisco Braga, Frederico Nascimento, and Henrique Oswald. In 1923, Nascimento was taken seriously ill, and Fernandez was designated his temporary substitute in the chair of upper-level harmony, an appointment which became permanent two years later (Kiefer 1986, 81). In 1936 he founded the Conservatorio Brasiliero de Musica in Rio de Janeiro, which he directed until his death. From 1949 onward was in addition Professor of Choral Singing at the Conservatorio Nacional de Canto Orfeonico.
He composed a three-act opera, Malazarte (1931-33), to a libretto by José Pereira Graca Aranha, who adapted it from his own play of the same title. For the premiere at the Teatro Municipal, Rio de Janeiro, 1941), the libretto was translated into Italian. Malazarte is a nationalist work in both its subject matter and its musical content, and is considered the first successful Brazilian opera of thistype (Béhague 2001). In 1941 Fernandez extracted a three-movement suite from the opera, the last movement of which, "Batuque" (an Afro-Brazilian folk dance), became very popular. He also composed one ballet, two symphonies, five symphonic poemss, two orchestral suites, one concerto each for piano and for violin, chamber music, about 80 compositions for piano, choral music, and 36 songs.