Marsha is the chief legal officer for Juvenile Law Center, America's first public interest lawyer center for children which she co-founded in 1975. Marsha has advocated for children involved in both the justice and child welfare systems throughout her career, challenging harmful laws and practices through litigation and appellate advocacy. She has participated in numerous cases before the United States Supreme Court, including several recent sentencing cases which applied a developmental lens to challenges to certain extreme sentences for youth. She is an adjunct professor at the University of Pennsylvania Law School and Temple Beasley School of Law. She is a graduate of the University of Pennsylvania and Temple Beasley School of Law.