She performed often with her husband, Peter Lind Hayes, for over 50 years, in a succession of films, television and radio shows and on the stage.

[3][5] She starred as Mrs. Aouda in Orson Welles's 1946 Broadway production of the musical Around the World in 80 Days, a role she reprised for The Mercury Summer Theatre of the Air radio adaptation.

[6] Healy was a member of the regular cast of Hayes's CBS-TV series, Inside U.S.A. with Chevrolet (1949–50), a revue-style series that producer Arthur Schwartz based on his successful Broadway show, Inside U.S.A.[7]: 359–360  Healy and Hayes were the first to sing the commercial jingle, "See the USA in Your Chevrolet", which later became a signature song for Dinah Shore.

WOR set up equipment in their house in suburban New Rochelle, New York, so that they could broadcast on weekday mornings from their home.

[1] Healy self-published a second book, Moments to Remember with Peter and Mary — Our Life in Show Business from Vaudeville to Video, in 2004.