The resourceful actress was first spotted by a talent agent while she was studying at Hollywood High School. She made her acting debut with the television series The Monroes in 1966 and made her film debut with the film With Six You Get Eggroll in 1968. With her powerful roles in films like The Baby Maker and Boxcar Bertha, Hershey started getting starring roles.
Hershey was brought up in a small sized bungalow and had the wish of being an actress since childhood. The multi-award-winning actress has worked in some of Hollywood's most notable films. She won herself an Emmy and a Golden Globe Award for the film A Killing in a Small Town in 1990. She won back to back Best Actress awards at the Cannes Film Festival, for her films Shy People and A World Apart. She was conferred with a Lifetime Achievement Award at the International Film Festival in Vienna.
In her illustrious career, she has worked with some of the world's best directors such as-William Wyler, Martin Scorsese, Jane Campion, Woody Allen, and Darren Aronofsky.
In 2010, Hershey was seen performing in James Wan's cult-classic, Insidious and Darren Aronofsky's Black Swan, which was an award-winning film. Her latest movie was The 9th Life of Louis Drax, which released in 2016.
She was in a relationship with David Carradine from 1969 to 1975. The couple together had a son. She married artist Stephen Douglas in 1992. The marriage was short-lived and the couple divorced after a year from their wedding. She was in a relationship with Naveen Andrews since 1999 but the couple parted their ways in 2009.