[4] In 1928, she made her debut at the Salzburg Festival as the Third Boy in Mozart's Die Zauberflöte, staged by Wallerstein and conducted by Franz Schalk.

She appeared first at the Bayreuth Festival in 1930 in Ring des Nibelungen as Erda, Waltraute, and Erste Norn, and as an Esquire and a Flower Maiden in Parsifal.

[4] She appeared in the world premiere of Julius Bittner's Das Veilchen on 8 December 1934,[3] directed by Wallerstein and conducted by Krauss, and the male lead role performed by Richard Mayr.

She made her debut in the 1937/38 season at the Metropolitan Opera in New York City as Fricka,[5] followed by Brangäne in Tristan und Isolde and Klytämnestra in Elektra by Richard Strauss.

[11] She performed in the world premiere of Franz Schmidt's oratorio Das Buch mit sieben Siegeln in Vienna on 15 June 1938,[3] conducted by Oswald Kabasta, with Rudolf Gerlach-Rusnak as Johannes.

Her repertoire in lieder is best documented by performances in the U.S. At a concert at Ann Arbor High School in Michigan in 1941, she sang three songs by Franz Schubert, An die Musik, Liebesbotschaft and the Erlkönig, as well as Mahler's Kindertotenlieder.

[13] Szánthó's voice is documented in several recordings from the Vienna State Opera, for example as Schwertleite in excerpts from Die Walküre on 1 March 1933, conducted by Krauss.

[3] In 1945/46, Eugene Ormandy conducted Beethoven's Ninth Symphony, with Stella Roman (soprano), Frederick Jagel (tenor) and Nicola Moscona (bass), the Philadelphia Orchestra and the Westminster Choir.