Brian Woito, 42, is accused of bypassing security and zipping up to the 102nd floor, the floor below the Sky Deck, on a freight elevator.
Officials say they detained him on the 32nd floor -- after he had wandered around for 16 minutes. Surveillance video shows the man strolling through the lobby.
Woito was charged with misdemeanor criminal trespassing on May 16, just weeks after authorities found 20 guns and two grenades inside the North Side home of another man who allegedly made a threat against Willis Tower.
Authorities said the recent incident was isolated and that security is their utmost priority.