Michael Ward, 18, and Kenneth Williams, 20, were each charged with one count of murder and two counts of attempted murder, McCarthy told reporters. They were also charged with two counts of aggravated battery with a firearm.
They will make their first appearance in court on Tuesday morning.
Ward confessed to shooting Hadiya and two others in late January in a case of mistaken identity, McCarthy said.
He and Ward thought they had spotted members of a rival gang at the park when police said Ward sneaked up on Hadiya and her friends and began shooting.
“Ward crept on foot, spraying gun fire,” McCarthy said.
Williams was the getaway driver, the superintendent said.
McCarthy said Ward was sentenced to two years’ probation in January 2012 for unlawful use of a firearm.
The charges come 12 days after Hadiya was shot to death at a park in what her godfather, Damon Stuart, described as an “ideal community” on Chicago’s South Side.
Her death occurred a week after she performed at one of the events surrounding Obama’s second inauguration.
The killing — which occurred in the city’s Hyde Park neighborhood near the Obamas’ Chicago home — drew the first couple’s attention.
First lady Michelle Obama attended Hadiya’s funeral and her husband wrote a note to Hadiya’s family that was printed on the funeral program: “We know that no words from us can soothe the pain, but rest assured that we are praying for you, and that we will continue to work as hard as we can to end this senseless violence.”
Hadiya, who often urged friends to stay away from gangs, was an honor student and band majorette at King College Prep School.
Her slaying — the 42nd in the city this year — also highlighted the problem of gun violence in Chicago. More than 500 people were fatally shot in 2012.
White House spokesman Jay Carney described her death as a “terrible tragedy.”
“The president has more than once, when he talks about gun violence in America, referred not just to the horror of Newtown or Aurora or Virginia Tech or Oak Creek, but to shootings on the corner in Chicago or other parts of the country,” Carney told reporters.
“And this is just another example of the problem we need to deal with.”
2013 has gotten off to a deadly start in Chicago — Pendleton was the year’s 42nd murder victim.
In 2012, 506 people were slain in the city.