The man appeared intoxicated, and a handgun was later found in his car, police told NBC5's Dick Johnson.
At 4:47 a.m., the man approached the security perimeter, which is about a block away from the Obama home. The man did not make any threats toward Obama or his family, the FBI said.
There are "Do Not Enter" and "Authorized Personnel Only" signs posted around the perimeter, according to News Affairs Officer Daniel O'Brien.
The man was questioned by the Secret Service and by Chicago police. The man may face charges, but none had been filed by 11 a.m.