The boy is facing two counts of first-degree attempted murder and two counts of aggravated battery, Chicago police spokesman Anthony Guglielmi told ABC News Saturday. Both are felony charges.
He was arrested around 1:24 a.m. on Saturday after police identified him as the primary suspect in the case, which also left a 31-year-old male wounded.
The little girl was shot in the lower neck area while out trick-or-treating in the Little Village neighborhood on Chicago's West Side on Thursday, police said. She remains in serious condition, according to a statement from Cook County Health, which oversees the hospital where she is being treated.
"The family of the 7-year-old girl who was shot in Little Village is grateful for the outpouring of love and support shown by all of Chicago and the nation," the statement read.
She was dressed in a bumblebee costume, according to the Chicago Sun-Times.
"Obviously, the little girl wasn't the target. We think two gangs were having a dispute and one of them shot at the other," Chicago Police Superintendent Eddie Johnson told reporters Friday morning. "She just was in the wrong place at the wrong time."
The 31-year-old man, who is believed to have been the intended target, was shot in the hand, according to Johnson.
"Those involved don't deserve to be in our city," he said. "I'm disgusted but committed to doing everything we can to find the cowards that would engage in a gun battle during the early evening hours while children are trick or treating."
Police did not release the name of the boy charged because he is a juvenile.