“He said, ‘Well if you don’t know what we do at the bank, you’re not the kind of person we want,’” Mr. Browne said in a 27-minute documentary made about him in 2019 by Jeff Dupre, a close friend and Emmy-winning filmmaker. “I said, ‘Well, if you can’t tell me what you do at the bank, then that’s not a place I want to work.’”

After that, he got it into his head that he might want to become a doctor, so he enrolled at St. George’s University School of Medicine, a so-called second chance med school on the island of Grenada. His roommates, Mr. Moore said, were a nun and an ex-convict. They got their degrees. He did not.

Mr. Browne began in real-estate at Halstead, focusing on Central Park West. Among his first deals was selling an apartment to Ian Schrager, one of Studio 54’s owners, who had recently been released from prison for tax evasion.

In subsequent years, the apartments that Mr. Browne sold got bigger and his clients glitzier — among them, Ms. Thurman, Alec Baldwin, Denzel Washington and Mariska Hargitay.

In 2002, Mr. Browne went to the Corcoran Group, where he won numerous awards. In an interview on Fox 5 New York around that time, Mr. Browne said he had gotten “hooked” into real estate “because I had such a passion for architecture.” But colleagues said his real love was being around people.

He lived according to Gore Vidal’s principle that no one should ever turn down the opportunity to go on television or have sex. He knew the interiors of many Central Park West co-op buildings because he had visited them (often after going to gay clubs like the Roxy, the Saint and the Sound Factory).