Police say 19-year-old Nahom Tsegazab has been charged with reckless discharge of a firearm.
Tsegazab was reportedly injured in the brazen shootout that killed two people and injured 24 others.
Police say he is being held in custody.
The shootout on Monday — which killed 14-year-old Shyanne Charled and 23-year-old Joshua Yasay — has sparked fears of American-style gun wars.
Ontario Premier Dalton McGuinty says increasing police presence is not the answer, adding community leaders need to consider alternative approaches.