Bryan Sutton, 62, of Flint, faces one felony count of aggravated criminal sexual abuse to a victim under 13 and one felony count of kidnapping.
At about 6 p.m. Saturday, Sutton allegedly sexually abused the victim inside a restroom stall at the McDonald's located in the 600 block of North Clark.
He was arrested moments later.
Sutton also allegedly battered a 61-year-old security guard who attempted to detain him, Chicago police said.
He was eventually placed into custody at the scene, and charged accordingly.
No additional information was made available.