The blaze, which was upgraded from three alarms to four alarms, erupted at the 58-story, 664-foot high mixed-use skyscraper on Fifth Avenue near West 56th Street just before 6 p.m.
Firefighters found the man, identified as 67-year-old Todd Brassner, unconscious and unresponsive when they entered the apartment.
"The apartment was entirely on fire," FDNY Commissioner Daniel Nigro said. "Members pushed in heroically, they were knocking down the fire and found one occupant of the apartment who is in critical condition."
Brassner was transported in critical condition to Mount Sinai St. Luke’s Hospital, where he died a short time later.
Four of the approximately 200 firefighters who responded suffered non-life threatening injuries, the FDNY said.
FDNY members remained at the scene after the fire was knocked down, searching floors and assessing smoke conditions. The cause of the fire remains under investigation.
"This was a very difficult fire," Nigro reported. "As you can imagine, the apartment is quite large, we are 50 stories up. The rest of the building had a considerable amount of smoke."
Brassner, an art dealer who purchased his high-rise apartment in 1996, had been struggling financially, the New York Post reported.
A Harrison native, Brassner was a 1969 graduate of the New Rochelle Academy, a private school that closed in 1987.
"Fire at Trump Tower is out," President Donald Trump tweeted. "Very confined (well built building). Firemen (and women) did a great job. THANK YOU!"
"Thank you to the amazing men and women of the NYFD who extinguished a fire in a residential apartment at @TrumpTower," tweeted Trump's son, Eric, who lives at the family's Seven Springs Estate in Bedford. "The @FDNY and @NYPD are truly some of the most incredible people anywhere!"
The building houses the $100 million penthouse condominium residence of the building's namesake and developer, President Trump.
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