Illinois Statutes Chapter 65. Municipalities § 20/21-5. Mayor; Term of office

(a) The mayor of the city of Chicago shall be elected in 1943 and quadrennially thereafter in a nonpartisan election. The candidate receiving a majority of the votes cast for mayor at the consolidated primary election shall be declared mayor. If no candidate receives a majority of the votes, a runoff election shall be held at the consolidated election, when only the names of the candidates receiving the highest and second highest number of votes at the consolidated primary election shall appear on the ballot. If more than one candidate received the highest or second highest number of votes at the consolidated primary election, the names of all candidates receiving the highest and second highest number of votes shall appear on the ballot at the consolidated election. The candidate receiving the highest number of votes at the consolidated election shall be declared elected.

(b) The mayor shall hold his or her office for 4 years beginning at noon on the third Monday in May following his or her election, and until his or her successor is elected and qualified.