The shooting happened at the Andersonville neighborhood's Primo Pizza in the 5600-block of North Clark Street just after 9 p.m.
Police said a 22-year-old man was inside the restaurant when multiple people, identified only as male, started arguing with him.
Someone in the group took out a gun and fired at the man, striking him multiple times before fleeing the scene on foot, police said.
The victim, shot in his thigh, was transported to St. Francis Hospital, where he is listed in fair condition.
There is no one in custody and Area Three detectives are investigating.
Police did not immediately provide further information about the shooting.
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