The Central Opera House [NYC], seating 2000, introduced Osterwald leading in Broken Hearts of Broadway in June 1944.

[citation needed] Osterwald went on to appear in such Broadway shows as Gentlemen Prefer Blondes, Bus Stop, Three to Make Ready, and The Golden Apple, for which she won an Outer Critics Circle Award in 1953.

She was best known for her television role of Stella O'Brien, the cranky housekeeper for the Hathaway family on the soap opera, Where the Heart Is in the 1970s and also as Mrs. Sophie Steinberg, the mother of David Birney and mother-in-law of Meredith Baxter on the comedy series, Bridget Loves Bernie.[6]: 136 .

[6]: 370 She appeared in several films, including Parrish (1961), The World of Henry Orient (1964), A Fine Madness (1966), Bank Shot (1974), Caddyshack II (1988) and As Good as It Gets (1997).

[7] Outside of acting, she was a frequent participant on the Ben Bagley's Revisited series of famous pop composers including albums of rarities by Cole Porter, Rodgers & Hart Vol.2 and Frank Loesser.