The Mandelbaum family is a wealthy Jewish American dynasty prominent in real estate, law, and professional sports ownership, with patriarch David Mandelbaum (born December 13, 1935, in Newark, New Jersey) at its helm. David's parents, Philip (1908-2004) and Ella Baum Mandelbaum (1911-1999), were Polish Jewish immigrants who rose from poverty—Philip worked as a bar mitzvah officiant before becoming a lawyer. David grew up in Maplewood, New Jersey, earned an A.B. from Princeton University in 1957 and a J.D. from Harvard Law School in 1960, and built a career in real estate law at Mandelbaum & Mandelbaum, P.A. (joined 1967), as general partner of Interstate Properties (1968, co-founded with Steven Roth), trustee of Vornado Realty Trust (1979), and director of Alexander's, Inc. (1995). A Democrat, he served three terms as New Jersey Assemblyman for Essex County from 1962 to 1967. David married Karen Krupnick in 1964; they have four sons—Richard (Princeton '87), Michael (Princeton '89), Jeffrey (Princeton '98), and Jonathan—and reside in Florida after years in Livingston, New Jersey. The family appeared on the 2005 Forbes 400 list with $900 million net worth and are minority investors in the Minnesota Vikings alongside the Wilf family. Known for philanthropy, particularly supporting Princeton University's Center for Jewish Life (CJL), where David and Karen funded construction, the Mandelbaum Lounge (2017), and the Mandelbaum Family Dining Pavilion (opened 2025) honoring David's parents; they are honorary CJL trustees. Sons Richard and Michael are involved in family businesses and Vikings operations. Michael Mandelbaum, an attorney managing family legal affairs, faced controversies including a 2013 aggravated assault charge (allegedly pushing wife Debra down stairs during argument), resolved via 2014 pre-trial intervention; his 2014 divorce involved allegations of faking Orthodox Jewish conversion to claim religious exemption from equitable asset distribution, earning him $6.6 million in 2012 per reports. Knighted by Pope John Paul II in 1999.