Professor Mandelbaum earned a B.S. from Brandeis University, a J.D. from American University, Washington College of Law, and an LL.M. from Georgetown University Law Center. She has devoted her career to working with children and families and has extensive experience in clinical legal education. Professor Mandelbaum began her legal career as a staff attorney at the Child Advocacy Unit of the Legal Aid Bureau in Baltimore, representing children in matters involving child abuse and neglect, termination of parental rights, custody, visitation, public benefits, special education, and foster care placement. She then went to the Georgetown University Law Center where, with another professor, she created a clinical program addressing the legal needs of families living in poverty. Prior to coming to Rutgers, she was an associate clinical professor at the University of California, Hastings College of the Law, where she taught in the Civil Justice Clinic, Hastings's clinical program.

As founding director of the Rutgers Child Advocacy Clinic, Professor Mandelbaum designed and developed the interdisciplinary and collaborative clinical program, which is aimed at comprehensively addressing the needs of low-income children and their families. She has written extensively about the legal representation of children, the legal and financial needs of kinship caregivers, and public policies concerning welfare.