Public Service Commissioner Robert Kenney is the agency's new chairman.
Missouri Gov. Jay Nixon announced Kenney's appointment Friday afternoon, barely three hours after Kevin Gunn's resignation became official.
Although Senate confirmation is required for an appointment to the commission, the governor chooses the chairman without any other review.
"As a long-time advocate on behalf of Missouri consumers, Robert Kenney is committed to protecting Missourians' hard earned dollars," Nixon said in a news release. "Chairman Kenney's leadership and expertise will serve him well in this new role."
Nixon named Kenney to the PSC in July 2009, and he was confirmed by the state Senate in January 2010.
Before his appointment, Kenney served as Attorney General Chris Koster's chief of staff.
He joined Koster's staff after working as a partner at the St. Louis law firm Polsinelli Shalton Flanigan Suelthaus PC - now known as Polsinelli Shughart.
He joined the law firm after several years of work as an assistant attorney general in the Consumer Protection Division.
Nixon noted the century-old, five-member Public Service Commission regulates investor-owned electric, steam, natural gas, water, sewer and telephone companies, with a mission to ensure Missouri consumers have access to safe, reliable and reasonably priced utility service - while allowing those utility companies an opportunity to earn a reasonable return on their investment, as required by state law.
The PSC also regulates manufacturers and retail dealers who sell new and used manufactured homes and modular units.