Rasheed Martin appeared before Cook County Circuit Judge Maria Kuriakos Ciesil after being extradited from Wisconsin.
Martin was arrested in Superior, Wis., last week. He is charged with first-degree murder in the drive-by shooting that killed Amari and wounded a 26-year-old woman. Both were shot in the chest. The woman was treated and released, but Amari died at a Chicago hospital.
Police said the bullet was intended for Amari's father, Antonio Brown, a ranking member of a street gang. Brown's attorney denied that.
Prosecutors said Martin fled with two uncharged co-defendants, who he implicated in a statement to police.
A public defender representing Martin says he is unemployed and penniless.