Javier Bello Portu took his first steps conducting an orchestra in San Sebastian with César Figuerido. He later moved to Paris where he continued his studies in the Conservatory of Music with maestros Biot, Fourestier and Bigot. He then went to the Chigiana Academy in Siena where, aswell as studying with Alciero Galliera, he was deputy to Franco Ferrara. In the 1970s, he worked in Geneva with Ernest Ansermet and graduated from the Mozarteum in Salzburg under maestros Herbert von Karajan, Deon Dixon and Leopold Hager.

He has conducted the orchestras of San Sebastian, Zaragoza and Santa Cecilia of Pamplona and has collaborated with the Symphony Orchestras of Madrid, Bilbao and Euskadi on various occasions. Many Basque composers have premiered their work under the baton of Javier Bello Portu, composers such as, Gorriti, Eslava, Aita Donostia, Olaizaola, Remacha and Mocoroa. In 1971, he was named Artisiic Director of the International Festival of Loyola, dedicated to Romanticism.

As a composer, he excells for the quality and variety of his choral music. Many of his pieces of music are points of reference within 20th century Basque choral repertoire, such as, “Soule y Llanto por la Muerte de Martín Zalacaín”. Several of his compositions have been used as required pieces in various different European competitions. The Choral Society of San Sebastian have recorded part of his repertoire.