Officials said 21-year-old Bryon Champ and 20-year-old Kewane Gatewood were charged in the shooting at Cornell Square Park, which is located in Chicago's southwest side.
Chicago Police Superintendent Garry McCarthy said that while the two played significant roles in the shooting, neither is believed to have pulled the trigger.
McCarthy said detectives are continuing the investigation.
Authorities say as many as three people opened fire Thursday on a basketball court in the Back of the Yards neighborhood. Among those injured were 3-year-old Deonta Howard, who is recovering from surgery after being shot near an ear, along with two teenagers.
Earlier Monday, police had said they were interviewing "several people of interest" in connection with the shooting and McCarthy sounded confident about case during a graduation ceremony for new officers.
"We are making great strides," McCarthy said then. "There's no doubt in my mind we're going to close this case quickly."
The shooting returned Chicago's gun violence problem to the nation's consciousness.
The assailants fired more than a dozen rounds from an assault-style rifle, police have said. They believe the shooting was gang-related, as several gang members were injured, although it's not yet clear who the intended target was.
Mayor Rahm Emanuel rode along with police officers late Sunday in particularly violent city neighborhoods.
Emanuel has made curbing violence a high priority, allowing the police department to spend millions of dollars in overtime to saturate high-crime areas with hundreds of additional officers.
Through Sept. 15, police say they've recorded 306 murders and 1,402 shooting incidents this year. That's down 20 and 22 percent, respectively, from the same period in 2012. Police say overall violent crime is down about 15 percent, according to new figures released Monday.