Garner was born in the Riverdale neighborhood in Bronx, New York. Her mother, Tami Gingold, a therapist, had a successful career in Israel around 30 years ago as a comedian, and her father is an art teacher. She has an older sister who is a producer. Garner is Jewish. Garner resides with her parents in their house in New York City. She considers actress Bette Davis to be a major influence on her acting style and citing Davis's performance in What Ever Happened to Baby Jane?