Palmer was born Patricia Betsy Hrunek on November 1, 1926,[2] in East Chicago, Indiana, the daughter[3][4] of Marie (née Love), an adoptee, who launched the East Chicago Business College before she married,[5][6][7][1][8] and Vincent Rudolph Hrunek (1894-1969),[9][10] an industrial chemist who immigrated from Czechoslovakia, and became a stay-at-home father.

[13] Some time after Palmer took an aptitude test at the Chicago YWCA, which indicated a flair for the arts, her father brought a coworker home for dinner, a former New York actor who recommended she study with David Itkin.

Having saved $400, she told her parents she was changing her name to Betsy Palmer and moving to New York City with Sasha Igler, who had a job in advertising.

[citation needed] A life member of the Actors Studio,[18] Palmer's stage work included a tour of South Pacific (as Nellie Forbush) and a summer-stock season in the title role in Maggie, the 1953 musical adaptation of What Every Woman Knows by William Roy and Hugh Thomas.

Palmer appeared as Kitty Carter in The Long Gray Line (1955), starring Tyrone Power and Maureen O'Hara.

She also played nurse Lt. Ann Girard (the main female character) in Mister Roberts (1955), starring with Henry Fonda, Jack Lemmon, James Cagney, and William Powell.

All the original productions had short runs, but she replaced other actresses in long-run shows, notably Lauren Bacall in Cactus Flower in 1967, and Ellen Burstyn in Same Time Next Year in 1977.

From 1989 to 1990, the actress appeared on Knots Landing as Virginia "Ginny" Bullock, the aunt of Valene Ewing (played by series star Joan Van Ark).

In 2005, at around 79 years old, she appeared as Trudie Tredwell in the horror short Penny Dreadful, and in 2007, at 81, as the older version of the title character in Waltzing Anna.