Bing entered Detroit politics as a Democrat in 2008. He announced his intentions to run for mayor in Detroit's non-partisan primary to finish the term of Kwame Kilpatrick. Kilpatrick had resigned during a corruption investigation. After winning the primary, Bing then defeated interim Mayor Kenneth Cockrel, Jr. and was sworn in as mayor in May 2009. Later that year, Bing was re-elected to a full term.