He subsequently debuted in Germany at the Berlin State Opera in the same work under Daniel Barenboim, in France as Fenton at the Theatre du Capitole in Toulouse, and in Great Britain at the London Proms of 2002 in Ravel’s L’Heure Espagnole.In the 2003/2004 season he made his debuts at the San Francisco Opera, Paris Opera and Vienna State Opera as Tamino; in September of 2004 at the Royal Opera, Covent Garden in September of 2004 as Ferrando. This was followed by his Italian stage debut as Alfredo at the Teatro Carlo Felice in Genoa. Other significant debuts included Alfredo at the Hamburg State Opera and at the Megaron in Athens, Fenton at the Theatre Royale Monnaie in Brussels. Ferrando at the Bavarian State Opera in Munich. A regular guest at all these theaters, Castronovo has since been heard as Alfredo in Vienna, London, Berlin and Aix en Provence, as Nemorino in Paris, Vienna, Nice and Berlin, as Belmonte in Munich and Rome, as Tamino in San Francisco, as Don Ottavio in Los Angeles, San Francisco, and Munich. He made his debut at the Salzburg Festival as Belmonte in Entfuerung.
In the summer of 2005 Castronovo sang his first Nadir in Les pêcheurs de perles at the San Francisco Opera, and has also also sung Nadir in Washington and San Diego. Several other new roles entered his repertoire in recent seasons; the title role in La Clemenza di Tito at the Bayerische Rundfunk in Munich, Rodolfo in La Boheme for the Michigan Opera, the Duke in Rigoletto in Bordeaux, and Faust in Pittsburgh.In the summer of 2008 he sang his first Tom Rakewell in a new production of The Rake’s Progress at the Royal Opera, Covent Garden; his debut as Edgardo in Lucia di Lammermoor in followed in 2009 in Brussels. In 2011 he sang his first Gennaro in Lucrezia Borgia opposite Edita Gruberova in Munich, as well as first Romeo in Romeo et Juliette for the Dallas Opera. Castronovo also added the title role in Berlioz’s Damnation de Faust to his repertoire in Nice.In June of 2012 he sang his first Nerone in Monteverdi’s L’Incoronazione di Poppea at the Teatro Real in Madrid.Among his other engagements in the past season were La Traviata in Aix en Provence and Vienna opposite Nathalie Dessay, Romeo in Romeo et Juliette at the Los Angeles Opera in November of 2011, and Cosi fan Tutte the Royal Opera House, Covent Garden. He made his long awaited debut at the Chicago Lyric Opera as Tamino in December of 2011.
Castronovo has also participated in revivals of more rarely performed works. He starred as Mylio in the revival of Lalo’s Le Roi D’Ys at Toulouse, opened the 2010/2011 season at the Paris Opera as Vincent in Mireille and debuted at the Festival de Montpellier in July of 2012 in Massenet’s Therese.He also recorded Mercadante’s Virginia for Opera Rara and sang Rossini’s Ermione in Santa Fe. A frequent soloist on the concert stage, he has appeared with the Chicago Symphony Orchestra, New York Philharmonic as well as in concerts in China, Japan, Russia, Sweden and Denmark.