The victim, a 9-year-old boy, was taken to the hospital Thursday evening where he was last listed in temporary serious condition.
The incident around the shooting is still being investigated, but police say the man's firearm discharged and struck the boy while he was clearing it.
The shooting happened on the 10000 block of Morang on the city's east side around 5:30 p.m.
After the boy was hit, the man transported him to the hospital.
"What we know about this story so far is no doubt it's tragic and it's unfortunate this is something I hear about way too often," said Chad King, a firearms safety instructor and president of the Black Bottom Gun Club.
A police report says the man was "clearing" his gun, which means he was making sure the weapon was not loaded.
"The basics of firearm safety are to always make sure you treat a firearm like it's loaded and clear it every time you pick it up," said King. "Ancillary and next to that is you make sure you never point a firearm in a direction that's not safe."
The boy's status as of Friday morning remains unknown.