Police said the shooting happened in the 700-block of South Wells Street just before 11:30 p.m.
A 35-year-old man was outside when a person he had been arguing with fired shots, police said.
The victim, shot in the back and grazed in the chin, was taken to Northwestern Hospital in serious condition.
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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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