Born and raised in Hollywood, Barbara Hershey took drama classes at Hollywood High. At 17 years, she landed a recurring role on TV's "Gidget", starring Sally Field. By the next season, she was in her own quickly-cancelled series, "The Monroes", playing one of five orphans in the old west.

Her first starring role was as Martin Scorsese's "Boxcar" Bertha in 1972. Barbara Hershey gained increased visibility with performance as Glennis Yeager, wife of test pilot Chuck Yeager, in Philip Kaufman's 1983 film, "The Right Stuff". In mid-decade, she followed the commercial success of "Hannah and Her Sisters" with unprecedented back-to-back wins for Best Actress at the Cannes Film Festival for "Shy People" and for A World Apart.

Barbara Hershey won an Emmy for Outstanding Lead Actress in 1990 in a Miniseries or Special for her turn as real-life murderer Candy Morrison in "A Killing in a Small Town". Throughout the nineties, Hershey made more small independent films and television projects.

As Madame Merle in Jane Campion's 1996 adaptation of the Henry James novel "The Portrait of a Lady", Hershey earned an Oscar nomination and won the Best Supporting Actress award from the National Society of Film Critics. In 1999, Hershey starred in "Drowning on Dry Land" with Naveen Andrews - with whom she entered into a romantic relationship. During a brief separation in 2005, Andrews fathered a child by another woman. He and Hershey have reportedly reconciled.

In 2001, Barbara Hershey was part of a largely Australian ensemble cast for the critically successful Australian film "Lantana", which also starred Kerry Armstrong, Anthony LaPaglia and Geoffrey Rush playing a troubled psychiatrist.