The man from Rochester was trying to climb over a divider when he fell from a second-level mezzanine into the lobby at the Hard Rock Hotel & Casino, police said.
The fall occurred about 4 a.m. on Monday.
Atlantic City police officers responded and found casino security performing CPR. The man was pronounced dead at the scene, a police spokesman said.
Atlantic City police urged anyone with information about the fall to call its Criminal Investigations Section at 609-347-5766.
Click here to follow Daily Voice Jersey City and receive free news updates.