CHICAGO (AP) — Mayor Rahm Emanuel's efforts to improve Chicago's schools are facing yet more upheaval after his hand-picked CEO, Jean-Claude Brizard, resigned just three weeks after the end of the city's first teachers strike in a quarter century.

Emanuel has called a news conference for Friday morning to introduce Brizard's replacement. She is Barbara Byrd-Bennett, a former teacher and administrator from Cleveland who had been filling in as Chicago's interim chief education officer and played a far more visible role than did Brizard in the teacher contract negotiations.

Both Emanuel and Brizard, who had only been on the job 17 months, said the decision was mutual and arose after questions about Brizard's management became a distraction to Emanuel's ambitious school reform goals.