She made her American debut at the Chicago Lyric Opera in 1957, as Mimi in "La bohème", opposite the great Swedish tenor Jussi Bjorling. Her Metropolitan Opera debut in New York took place on November 14, 1959, as Violetta in "La traviata", a part that quickly became her signature role. She sang at the Metropolitan Opera for seventeen seasons to great acclaim in roles such as Lucia ("Lucia di Lammermoor"), Gilda ("Rigoletto"), Mimi ("La bohème"), Marguerite ("Faust"), Juliet ("Romeo and Juliet"), Manon ("Manon"), the four heroines in "Les contes d'Hoffmann", etc. She also sang in San Francisco, Los Angeles, Philadelphia, etc., while making several appearances on American television. 