Hardiman, who helms a group that works to reduce violence, was arrested after his wife came into the Hillside Police Department alleging that she was beaten, Hillside Police Chief Joseph Lukaszek said.
Lukaszek said Hardiman's wife had visible injuries.
Police then went to Hardiman's home, saying they had probable cause to arrest him.
He was charged with one count of domestic battery and will appear in bond court Saturday.
"We are troubled to learn of the allegations reported in the media concerning Mr. Hardiman, director of CeaseFire Illinois, and take these allegations very seriously," Gary Slutkin, the executive director of CeaseFire's parent organization, Cure Violence, said in a statement.
Slutkin said CeaseFire and the University of Illinois, where the organization is based, have "zero tolerance for anyone with domestic-related charges, or crimes against women or children, currently or in their background."
"CeaseFire has developed strict policies to make sure that all employees remain in a good standing," Slutkin said.