Gruberová made her debut at Glyndebourne in 1973 as the Queen of the Night. She achieved international recognition in 1976 when she sang Zerbinetta in the premiere of a new production of "Ariadne auf Naxos" by Richard Strauss. She first appeared at the Metropolitan Opera in 1977, again as the Queen of the Night. In 1977, she first appeared at the Salzburg Festival, as Thibault in Verdi's "Don Carlo", conducted by Herbert von Karajan. She appeared as Gilda in Jean-Pierre Ponnelle's 1982 film of "Rigoletto" opposite Ingvar Wixell and Luciano Pavarotti, and in his 1988 film of Mozart's "Così fan tutte" opposite Delores Ziegler and Ferruccio Furlanetto. Gruberová made her Royal Opera House debut as Giulietta in Bellini's "I Capuleti e i Montecchi" in 1984. Other important roles include the title role of Verdi's "La traviata" ad Donizetti's in "Lucia di Lammermoor", Konstanze in Mozart's "Die Entführung aus dem Serail", the title role in Massenet's "Manon" and Oscar in Verdi' "Un ballo in maschera". She appeared as Donna Anna in Mozart's "Don Giovanni" at La Scala in Milan in 1987, as Marie in Doizetti's "La fille du régiment" in 1987, in the title role of Rossini's "Semiramide" in Zürich in 1982, and as Elizabeth I in Donizetti's "Roberto Devereux" in Vienna in 1990. In 2006, she added the title role in Bellini's "Norma" to her repertoire, at the Bavarian State Opera.