d'Avalos acknowledged that the Italian composer Antonio Favasta convinced his parents to allow him to study music.
He graduated with honours from the Conservatory of San Pietro a Majella in Naples, with a degree in composition.
In 1972, Nino Rota recruited d'Avalos as a composition teacher to the Conservatory in Bari, where he remained until 1979. d'Avalos then accepted a faculty post at the Naples Conservatory, where he remained until 1998.
He made commercial recordings for such labels as ASV, IMP, Chandos, Brilliant, Amadeus, and Nireus.
His other compositions include: His awards and honours included: In 2005, Bietti published d'Avalos' book La crisi dell'Occidente e la presenza della storia – Il significato del ventesimo secolo attraverso l'evoluzione della musica (The Crisis of the West and The Presence of History – The Meaning of the Twentieth Century Through the Evolution of Music).