[3] Stevens was engaged as a member of the Vienna State Opera ensemble at the Teatro Colón in 1938 (as Octavian in Der Rosenkavalier) and was invited to the Glyndebourne Festival in 1939 where she was heard as Dorabella and Cherubino.

Three weeks later at the Metropolitan Opera in New York City, she sang Mignon in a Saturday matinee broadcast in a cast that included Richard Crooks as Wilhelm Meister and Ezio Pinza as Lothario.

Her other operatic roles included Fricka in Wagner's The Ring of the Nibelung, Marfa in Mussorgsky's Khovanshchina, Giulietta in The Tales of Hoffmann, and Prince Orlovsky in Die Fledermaus.

Stevens' acclaimed RCA Victor recording of the complete opera Carmen, conducted by Fritz Reiner and co-starring Jan Peerce, Robert Merrill and Licia Albanese remains a best-seller and has been continuously available since its original 1951 release.

After her retirement from the operatic stage, Stevens served as General Manager of the Metropolitan Opera National Company until 1966 and later coached the new generation of singers at the Met.

[6] She remained director until the company dissolved in 1968, during which time she mentored several prominent singers with the MONC, including sopranos Clarice Carson, Maralin Niska, Mary Beth Peil, Francesca Roberto, and Marilyn Zschau; mezzo-sopranos Joy Davidson, Sylvia Friederich, Dorothy Krebill, and Huguette Tourangeau; tenors Enrico Di Giuseppe, Chris Lachona, Nicholas di Virgilio, and Harry Theyard; baritones Ron Bottcher, John Fiorito, Thomas Jamerson, Julian Patrick, and Vern Shinall; bass-baritones Andrij Dobriansky, Ronald Hedlund, and Arnold Voketaitis; and bass Paul Plishka.

[7] Established in 1964, this award sought "to bring a declaration of appreciation to an individual each year that has made a significant contribution to the world of music and helped to create a climate in which our talents may find valid expression".

In 1939, Stevens married Walter Surovy, an Austrian stage and screen actor she met during her European years, after he fled the Nazis to New York.