The move comes just days after Hardiman was arrested for a domestic battery complaint lodged by his wife.
Hardiman was released from jail after posting bond Saturday night.
Hardiman said he intends to set up his own chapter of CeaseFire and that he does not appreciate CeaseFire's leadership not standing behind him.
"Following arrest charges filed for domestic battery this past weekend, Tio Hardiman has been placed on administrative leave. On June 30, his contract will expire. Mr. Hardiman is no longer a representative of CeaseFire, its parent organization Cure Violence, or the University of Illinois at Chicago School of Public Health. Effective today, a search will be conducted for a permanent replacement," a CeaseFire release said.
Hardiman was represented by a public defender Saturday.
Hardiman was arrested Friday after an argument with his wife allegedly turned physical at the couple's Hillside home.
"I am Mr. Ceasefire and I got caught up in a situation and I am not here to point fingers and blame nobody," Hardiman said. "The verdict is still out. I can't really speak about the case. Things happen for a reason and liberation comes in many forms."
Hardiman was released on a $20,000 bail.