[3] He attended Stuyvesant High School but dropped out in order to pursue dual careers in the book business (eventually upon his father's death taking over the elder Greenburger's agency) and real estate.
Summarily attending Washington Irving High School at night, he went on to get his GED and then an undergraduate degree from Baruch College in public administration.
Greenburger went on to earn the moniker "the co-op king of New York" for his specialty of converting prewar apartment buildings into occupant-owned residences, which offered tenants the ability to become owners and create new wealth.
[4] His literary agency, which still carries his father's name, has at different times represented, among other authors, Dan Brown, James Patterson, Nicholas Sparks, Nelson DeMille and George Bach.
[5] Today he is the CEO of the real estate firm he brought into being, Time Equities, Inc. which is set to open the billion dollar, 64 story mixed-use residential and commercial building 50 West Street in lower Manhattan adjacent to the Brooklyn Battery Tunnel.