Sean Morrison was appointed Cook County Commissioner of the suburban 17^th District on July 22, 2015 and elected by the voters of the 17^th District to serve a full, four-year term on November 6, 2018. On January 19, 2022, Commissioner Morrison announced his campaign for re-election for Commissioner of Cook County’s 17^th District.

Commissioner Morrison’s focus on the Cook County Board has remained squarely on fighting irresponsible tax and spend policies, advocating for innovative reform measures that will reduce the cost of government, increase efficiencies, and improve services. In 2017, Commissioner Morrison authored the ordinance that led to the successful repeal of the Cook County Sweetened Beverage ‘Soda’ Tax. Sean also fought to successfully defeat proposed increases to the county's gasoline tax, cable tax, and other tax increase proposals.