The teen turned himself in, police say. He has been charged with two felonies including facilitating a riot and second-degree conspiracy.
Two more suspects remain on the loose, police say. They have not been identified.
Investigators released video of the suspects last week.
The shooting happened around 6:45 p.m. on Saturday, April 8.
According to investigators, the suspects confronted and assaulted an 18-year-old male victim while exiting the food court.
The victim's friends then engaged in an altercation with the suspects.
"During the fight, one suspect removed a handgun from his waistband and began firing multiple rounds," police said in a news release.
The 18-year-old, his 16-year-old friend and another victim were all injured in the shooting.
All three victims suffered non-life-threatening injuries.
Anyone with information is asked to call Delaware State Police at 302-365-8467.