She sang and recorded throughout the 1930s and 1940s with the Emery Deutsch, Rudy Vallee, Eddie Duchin, Richard Himber, Hal Kemp, Hudson-DeLange, Raymond Scott, Teddy Wilson and Freddie Rich orchestras.

After working the vaudeville circuit, the late 1930s saw Wynn landing at radio station WNEW[9] in New York for a 13-show-per-week stint and honing her talent under the mentorship of Jimmy Rich, the singing coach to Dinah Shore, Bea Wain, and Barry Wood, among others.

[10] Wynn is perhaps best known for dubbing Rita Hayworth's singing voice in several films, including The Strawberry Blonde (1941),[11] My Gal Sal (1942), and You Were Never Lovelier (1942), where she introduced the Kern-Mercer standard I'm Old Fashioned.

Wynn's career was cut short abruptly in 1949 by the loss of her voice following the surgical removal of a cancerous tumor, which resulted in a severed facial nerve.

[13] Wynn appeared on the silver screen, often as a nightclub singer, in such films as Million Dollar Baby (1941), Pardon My Sarong (1942), Right Guy, (1943), Princess O'Rourke (1943), Is Everybody Happy?