Mol was born in Deep River, Connecticut where her mother, Janet, is an artist and teacher and her father is a school teacher at RHAM. She went to high school with Broadway actor Peter Lockyer. They performed in school musicals and plays together. Her brother, Jim Mol, is a director and editor in the film industry. Mol attended The American Musical and Dramatic Academy and graduated from the William Esper Studio. After summer stock in Vermont, she took a job for a while as an usher at Angelika Film Center. She was living in a Hell's Kitchen walk-up when she was noticed by a talent agent who spotted her working as a hat check girl at Michael's Restaurant in New York. Mol's first acting job was in a Coca-Cola commercial.