A body was pulled from the water shortly after 9 a.m. Tuesday morning.
Police helicopters and divers began searching after 10 p.m. Monday night when witnesses reported seeing the man fall from a sailboat. Navy Pier was the site of Chicago's only lakefront Fourth of July fireworks show earlier in the evening.
The relatives of 30-year-old Christopher Szmajlo, of Orland Park, say it was his remains that were recovered Tuesday.
Divers made the discovery in about 30 feet of water near a break wall about a half-mile offshore east of the lighthouse.
Emergency crews say that they first responded to calls about a report of a man who fell or jumped into the water east of Randolph Drive at approximately 10:15 p.m. Monday. Authorities said people in another boat tried to help Szmajlo after seeing him going under the water and gasping for air. He was not wearing a life jacket, authorities said earlier.
With the aid of a Coast Guard helicopter, divers used GPS technology Tuesday morning in their search of a specific area.
"His shirt was recovered last night from this area, so we went right back to that same area and we located the victim within 25 yards of the markers that we had placed from last night," said the Chicago Police Marine Unit's Sgt. Ray Mazzola.
Area 3 police detectives have now launched a death investigation.
Family members say that Szmajlo was a great guy, with a real zest for life, and the last thing they expected was for him to die celebrating the Fourth of July.
"It was a shock, and he was in real good shape and worked out and everything, and everyone had the hope he will make it to shore," said the victim's uncle, Rich Gierut.
