Has a brother named Jerry.
In a botched 1980 surgical procedure, Dr. Norman Scott, longtime physician for the New York Knicks (1978-2005), operated on Peggy's right knee instead of her injured left knee. After she noticed the mix-up in the recovery room, he had to wheel her back in and fix the other one. She sued him for malpractice and was awarded $460,000 in 1985.
She had an encyclopedic mind and appeared in many TV quiz shows in the 1960s.
She studied drama at HB Studio in Greenwich Village in New York City.
The daughter of Raymond James and Margaret Cass.
Was one of Jack Paar's stable of comedy players during his run as host of "The Jack Paar Tonight Show" (1957) from 1958-62, a period in which she also appeared regularly as a panelist on numerous game shows.
Won Broadway's 1957 Tony Award as Best Supporting or Featured Actress (Dramatic) for "Auntie Mame," a part that she recreated in an Oscar-nominated performance in the film version of the same name, Auntie Mame (1958).