Gershon was born, as Gina L. Gersohn (sic), in Los Angeles, to Mickey Gershon (née Koppel) an interior decorator, and Stan Gershon, who worked in the import-export business and sales. She was raised in a Jewish family in Los Angeles's San Fernando Valley. She has an older brother and an older sister.
Gershon went to Collier Street Elementary School and Woodland Hills Academy (formerly Parkman Junior High). She attended Beverly Hills High School and started acting at the age of 14. After graduating from high school in 1980, she moved to Boston to attend Emerson College. She transferred to New York University, and graduated with a BFA in drama and psychology/philosophy in 1983.
She has said she always wanted to be an actress, but her career began in music and dance.
