Rebecca Creskoff was born and raised in Philadelphia, Pennsylvania. She is the daughter of Betty Jane Creskoff, a home maker, and Howard Creskoff a lawyer, and has an older sister.

Her father is of Russian Jewish decent and her mother is of mostly English and German ancestry--a true Midwestern protestant. The New Yorker Magazine describes Creskoff as "immensely gifted, with formidable technique" and named her one of the best performers of 2010. Creskoff studied English literature at the University of Pennsylvania and then, following the advice of her friend and mentor Debra Messing, chose to hone her craft more seriously at the prestigious MFA acting training program at New York University.