Levar Jones, 26, was charged with felony counts of reckless conduct and having an invalid firearm owner's identification card and misdemeanor counts of endangering the health and life of a child, the Chicago Tribune reported Thursday.
Police said the 7-year-old found the loaded gun Wednesday night under a bed and accidentally shot his sleeping younger brother through the top of his left leg.
Emergency crews took the baby to University of Chicago Comer Children's Hospital where his condition stabilized and he was sleeping early Thursday, the Chicago Sun-times reported.
A mother and grandmother, as well as four other children from the family, were in the home at the time of the shooting, police said.
Five other guns were found in the home, authorities said.