65 ILCS 5/6-4-13
The mayor in cities of 50,000 or more population shall appoint a budget and finance director whose functions shall include the preparation, under the direction of the mayor, of the annual municipal budget, the general duties of budget director as provided by ordinance, and any other financial duties allocated to the budget and finance director by order of the mayor or by city council ordinance. The budget and finance director shall serve at the pleasure of the mayor. The qualifications of a budget and finance director shall be outlined in an ordinance by the city council and must include a broad background in accounting (preferably municipal accounting), the ability to evaluate and establish systems and procedures, and administrative ability.
65 ILCS 5/6-4-13