William Zeckendorf

William Zeckendorf, Sr.
Zeckendorf in New York, 1952
Born	(1905-06-30)June 30, 1905 Paris, Illinois, U.S.
Died	September 30, 1976(1976-09-30) (aged 71) New York City, New York, U.S.
Nationality	American
Occupation	Real estate developer
Spouse(s)	Irma Levy
Children	William Zeckendorf, Jr. Susan Zeckendorf Nicolson

William Zeckendorf, Sr. (June 30, 1905 – September 30, 1976) was a prominent American real estate developer. Through his development company Webb and Knapp—for which he began working in 1938 and which he purchased in 1949—he developed a significant portion of the New York City urban landscape. Architects I. M. Pei and Le Corbusier have worked for Zeckendorf on many of his projects.

Zeckendorf was born to a Jewish family in Paris, Illinois, the son of a hardware store manager. His family moved to New York City when he was three years old. He attended New York University but dropped out to work at the real estate company of his uncle, Sam Borchard. He soon left his uncle's firm to work for Webb & Knapp, a small New York building manager and brokerage.

Zeckendorf's most notable property acquisition, and potential development of a "dream city" to rival Rockefeller Center, was a 17-acre (69,000 m²) site along the East River between 42nd Street and 48th Street. In a now celebrated transaction in December 1946, the prominent architect Wallace Harrison and Nelson Rockefeller bought the site from him for $8.5 million (equals $104 million in 2016) and Nelson's father John D. Rockefeller, Jr. subsequently donated this land for the building of the United Nations Headquarters.

Zeckendorf also owned New York's famous Chrysler Building and the venerable Hotel Astor in Times Square. He purchased Chicago's famous Robie House in 1958 before transferring ownership to the University of Chicago. He developed two of I. M. Pei's early skyscrapers—the Mile High Center (now part of Wells Fargo Center) in downtown Denver, and Place Ville-Marie in downtown Montreal.