Barnett was born Gershon Swiatycki on the Lower East Side of Manhattan.
He returned to the United States in the 1990s to diversify into real estate, purchasing shopping malls and office buildings in the Midwest.
[1] In 1994, he joined Kevin P. Maloney's Property Markets Group as a principal[3] and made his first New York City purchase, the Belnord apartment building.
In 2003, Barnett partnered with the Carlyle Group to build The Orion, a 60-story luxury tower on 42nd Street.
[1] Barnett is a 2011 American Institute of Architects (AIA) Heritage Ball honoree.