Born in Puerto Rico, Justino Diaz made his professional debut at 17 in a San Juan Production of Gian Carlo Menotti's The Telephone. After studying at the New England Conservatory, he joined the Metropolitan Opera Studio and soon won the 1963 Metropolitan Opera National Auditions, acquring a contract with the Metropolitan Opera. In the same year, he made his New York debut, in a Carnegie Hall concert performance of I Puritani with Joan Sutherland, Nicolai Gedda, and the American Opera Society.
Acclaimed by TIME magazine as "one of the richest manliest basses around," Justino Diaz has performed with the world's leading opera companies, including the Berlin ,Cologne, Canadian Opera, Covent Garden, Gran Teatro del Liceo in Barcelona, Hamburg Staatsoper, la Scala, Metropolitan Opera, Munich Staatsoper, New York City Opera, San Francisco Opera, Teatro Colon in Argentina, Vienna Staatsoper, and the opera companies of Boston, Cincinnati, Dallas, Philadelphia, Pittsburgh, San Diego, Seattle, Toronto, and Washington.
Mr. Diaz has also been highly praised for his appearances with the orchestras of Europe and South America, as well as the major North American orchestras, among them the Boston Symphony, Cleveland Orchestra, Los Angeles Philharmonic, National Symphony, New York Philharmonic, and Philadelphia Orchestra. A frequent participant at the summer festivals of Edinburgh, Ravinia, Salzburg, Spoleto, Wolf Trap, Casals Festival, Cincinnati May Festival, and Mostly Mozart, he has collaborated with such renowned conductors as Herbert von Karajan, Sir Georg Solti, Zubin Mehta, Carlos Kleiber, Seiji Ozawa, James Levine, Lorin Maazel, Leonard Bernstein, Erich Leinsdorf, Pablo Casals, and Charles Munch.
In the 1987-88 production of Otello at the Metropolitan Opera, Justino Diaz appeared as lago. He has won great acclaim and worldwide recognition for this role, which he portrayed opposite Placido Domingo and Katia Ricciarelli in Franco Zeffirelli's film, Otello. Mr. Diaz regularly returns to the opera companies of Vienna, Pittsburgh, New Orleans, Los Angeles, and Miami, and has appeared twice at Carnegie Hall in New York, singing the Verdi Requiem with the Oratorio Society of New York and joined a steir-studded cast in tribute to Richard Tucker.
During Mr. Diaz' prestigious singing career, he performed with Leontyne Price in Samuel Barber's Antony and Cleopatra, as part of the gala opening of the Metropolitan Opera House at Lincoln Center, and appeared in the world premiere of Ginastera's Beatrix Cenci, which opened the Opera House at the Kennedy Center in Washington, D.C. His Kennedy Center premiere performances included the long and difficult title role of Verdi's Attila, with the Washington Opera, and his part in Alexander's Feast, as part of the Kennedy Center's Handel Festival. Mr. Diaz not only portrayed Escamillo in the Metropolitan Opera's Carmen, but also made his cinematic debut in the role for the acclaimed Salzburg version of the opera, which was produced and directed by Herbert von Karajan for worldwide distribution.
Mr. Diaz, along with Marilyn Horne, Beverly Sills, and conductor Thomas Schippers, made international headlines in the revival of Rossini's L'Assedio di Corinto, a role he repeated at the Metropolitan Opera permirere, both on stage and on tape. At the Edinburgh Festival, he sang in the La Scala production of La Pierra del Paragone and the Cologne Opera's 11 Barbiere di Siviglia. At Carnegie Hall's Rossini Festival in 1983 he made his first appearance as Orbazzano, opposite Marilyn Horne as Tancredi, another addition to his impressive list of Rossini performances.