Professor Mandelker received his B.A. (1947) and LL.B (1949) degrees from the University of Wisconsin, and his J.S.D. (1956) degree from Yale University. He was the Stamper Professor of Law at Washington University in St. Louis (1962-2022) and previously taught at Indiana University (1952-1962) and Drake University (1949-1951). Professor Mandelker has published several books, including treatises on Land Use Law and NEPA Law and Litigation, and law school casebooks Planning and Control of Land Development and State and Local Government in a Federal System, in several editions. He also is the author of reports on Planned Unit Development and Street Graphics and the Law. His many articles consider topics such as manufactured housing, group homes, and land use litigation. He has been cited three times by the U.S. Supreme Court.

Professor Mandelker was an Attorney-Advisor with the federal Housing and Home Finance Agency, 1951-1952, was on the Board of Directors of the American Planning Association, was the Chair of their Divisions Council, and was the principal consultant for their report on model state zoning and planning legislation. He consulted widely with states and municipalities on sign ordinance and land use regulation questions, including the state of Hawaii on their state land use system, and the city of New Orleans on a charter amendment that mandated comprehensive plans. He also advised national organizations, such as the Transportation Research Board, which is the national organization for research on transportation problems, and was a Senior Fellow of the Urban Land Institute. He received the Daniel A. Curtin award from the State and Local Government section of the American Bar Association.