The man, who is in his early 40s, fell about 1:15 p.m. EST when a Regal Cinemas employee approached him to request he get off the railing, the Atlanta Journal-Constitution reported.
Witnesses said the man,who had purchased a movie ticket, bounced off the second floor as he plunged to the first-floor food court, Gwinnett County police said.
Gwinnett police Sgt. Rich Long said the interruption of his fall "was a lucky enough impact" to prevent the man from being killed upon landing in the food court.
The county fire department said the man was in serious condition but alert and breathing after the fall, the newspaper said.
The Journal-Constitution said two other people have jumped to their deaths in the same vicinity in the past several years. Long said investigators were trying to determine if Sunday's incident was an accident.
"We don't know," he said.