Officers responded to a report of an armed person inside Rockford Billiards Cafe, 1434 N. Main St.
Joshua Pulliam, 28, was in possession of a holstered loaded handgun and a detached extended magazine.
Pulliam was charged with unlawful use of a weapon by a felon and was booked into the Winnebago County Jail.
He is scheduled to appear in court on April 6.