Mollen was born and raised in Phoenix, Arizona. Mollen's father is Jewish, and she was raised culturally Jewish. She has a sister and a brother. Her work in local theater led to work with The Old Globe in San Diego, California, The Idywild School, and the Oregon Shakespeare Festival in Ashland, Oregon. She graduated from University of California, Los Angeles's School of Theater, Film, and Television. While there she broke into the film industry. Her father, osteopathic physician Dr. Art Mollen, has published five books on health topics and has appeared as a health expert on The Oprah Winfrey Show and other media outlets.