Jaron Jackson, 18, pleaded to concealed weapons charges last month and learned his punishment Thursday.
Brandon Davis, 11, died after being shot outside the Lonnie Burten recreation center after a fight broke out.
Although Jackson didn't fire the gun, the judge says Jackson must take responsibility for what his actions created.
"I'd like to send my heart out to the family. It was a tragedy and a terrible loss," Jackson said.
So many people turned out, the judge had to delay the sentencing to add extra chairs to the courtroom.