Mayor Hannemann resigned from office on July 20, 2010, and formally became a candidate for Governor of Hawaii. Hanneman's resignation necessitated a special mayoral election to fill the remainder of the mayor's unexpired term.
The Honolulu City Council set the date for the mayoral election for September 18, 2010.
An August 2010 poll conducted by Hawaii News Now and the Star-Advertiser showed Peter Carlisle at 49 percent, Kirk Caldwell with 25 percent, Panos Prevedouros with 11 percent, and Rod Tam being favored by 4 percent of potential voters. Carlisle won the election.