Cronin is the current Chairman of the DuPage County Board. In this position, Cronin spearheaded the development of the DuPage ACT Initiative designed to improve efficiency and encourage resource sharing across county government and its independently administered agencies. Cronin has also provided leadership to Transform Illinois, a non-partisan collaboration of public officials, civic leaders and research institutions advocating for government efficiency. Prior to serving as DuPage County Board Chairman, Cronin was a member of the Illinois General Assembly, serving one term in the House of Representatives before moving to the Illinois Senate.