The 2006/07 season marked a series of role debuts such as Rodolfo in La bohème, Nadir (Les pêcheurs de perles), the Duke in Verdi's Rigoletto, and Mylio in Édouard Lalo's Le roi d'Ys.

In the Summer of 2011, Castronovo made his debut with the Aix-en-Provence Festival, appearing with French soprano Natalie Dessay in Verdi's La traviata.

In August 2011 he appeared at the Royal Albert Hall with the John Wilson Orchestra in the now celebrated series of Proms, dedicated to the great Hollywood musicals.

In the summer of 2014, he performed the title role in Hector Berlioz's La damnation de Faust, standing in for Ramón Vargas, at the Verbier Festival.

Recent musical projects include performances of traditional Neapolitan songs, with a small ensemble of guitar, accordion, percussion and bass.