She was discovered in the late 1940s by Arturo Toscanini, who engaged her for a series of performances with his NBC Symphony Orchestra in New York City. Toscanini described her at the time as "the find of the century". She appeared as Nanetta in his two-part NBC radio broadcast of Verdi's Falstaff, in 1950, one of Toscanini's most acclaimed performances. It was also released on LP, 45-RPM, and CD.
Stich-Randall travelled on a Fulbright Scholarship to Europe, where she made her name as a singer. She made her European debut in Florence and won a competition in Lausanne the following year. This led to appearances with the Basel Opera in Switzerland.
Stich-Randall was a regular performer with the Vienna State Opera and at the Salzburg Festival. From 1955, she was a regular at summer events at Aix-en-Provence in France, where her portrayals of Donna Anna in Don Giovanni and the Countess in The Marriage of Figaro were highly esteemed.
In 1962, the Austrian Government awarded her the title of Kammersängerin, given to esteemed vocal artists. Stich-Randall made her debut at the Chicago Lyric Opera as Gilda in Rigoletto in 1955. She first sang at the Metropolitan Opera in New York City in Così fan tutte in 1961 and remained on their roster of singers until 1966. Stich-Randall made her Boston debut in 1963 for the Peabody Mason Concert series.
- Playbill "Soprano Teresa Stich-Randall Dies at 79" 23 July 2007
- Her first appearance in a major production was at the Bushnell Center for the Performing Arts in 1943.AP via the Washington Post, "Acclaimed Soprano Teresa Stich-Randall, 79" 25 July 2007
- New York Times "Teresa Stich-Randall, 79, American Operatic Soprano, Is Dead" July 24, 2007 (with correction, August 4, 2007)
- Adieu à Donna Anna (French)
- Christian Science Monitor, 16-Feb-1963, Louis Chapin, "Stich-Randall delights in Mason series", Boston