John Theodore Chisholm (born March 14, 1963) is an American prosecutor and the district attorney of Milwaukee County, Wisconsin, serving since 2007. Prior to his election as district attorney, Chisholm was an assistant district attorney in the office, supervising its gun-crime unit. Chisholm has prosecuted several notable cases in Milwaukee, including those of Milwaukee alderman Michael McGee, Jr., serial killer Walter Ellis, and several associates of Wisconsin Governor Scott K. Walker. Conservative groups have criticized Chisholm for initiating an investigation into possible violations of Wisconsin's campaign finance laws during the 2012 Wisconsin gubernatorial recall election.