He took part in revivals of neglected opera such as La donna del lago, opposite Montserrat Caballé, and Le siège de Corinthe, opposite Beverly Sills, and took part in the creation of new works, such as Aladino e la lampada magica by Rota, and Luisilla by Mannino.

He began an international career in the early 1970s, with debut at the Vienna State Opera, the Salzburg Festival, the Paris Opéra, the Metropolitan Opera, etc., and began expanding his repertory to include more dramatic roles, notably Arnold, Don José, Manrico, Radames, Otello, Cavaradossi, Calaf, etc.

In his later career he became known for excessively long-held high notes (such as in "Di quella pira" and "Nessun dorma") and temperamental or bizarre behaviour, on and off stage. He caused a major scandal in 1978 when, after throwing his prop sword at the conductor Herbert von Karajan, he furiously left the stage just before the famous cabaletta "Di quella pira" during a public dress rehearsal of Il trovatore at the Vienna State Opera.