Before leaving the show, she briefly understudied the title role of Louise and played the part for one performance without having had an opportunity to rehearse Act 2.

[5] In 1962, she graduated to a leading role, playing the ingenue in I Can Get It for You Wholesale, opposite Elliott Gould and Sheree North (the show marked Barbra Streisand's Broadway debut at age 19).

In 1981, Cooper created the supporting role of Jan Donovan, the wife of Tess Harding's ex-husband Larry, in the Lauren Bacall vehicle Woman of the Year.

She also reprised her role of Jan Donovan in the national touring production of Woman of the Year, starring Barbara Eden, from April 3, 1984, until September 16, 1984.

Cooper's television appearances include Alice, where she was reunited with Linda Lavin (singing "It's All in the Game"), Kate and Allie, Cheers (as Lilith Sternin's mother Betty), Law & Order, The Nanny and Caroline in the City.