NSAC director Keith Kizer resigning

MMA Live Extra: Kizer Resigns (2:30)

Brett Okamoto reacts to the resignation of Nevada State Athletic Commission executive director Keith Kizer. (2:30)

LAS VEGAS -- Keith Kizer, executive director to the Nevada State Athletic Commission since May 2006, confirmed his resignation from the position on Friday.

Kizer, 47, has elected to return to the Nevada attorney general's office, where he was a deputy attorney general prior to assuming the NSAC position. His resignation will take effect on Jan. 27.

"I'm an attorney by trade," Kizer told ESPN.com. "There are no fights scheduled this month. It's a new calendar year. Everything is looking good for a big spring. I was almost like, 'If I don't do this now, then when?'"

The NSAC will start the process of replacing Kizer immediately, according to NSAC chairman Francisco Aguilar.

"The board is grateful to Keith for this nearly eight years of dedicated service, which included the Commission's strongest years with regard to healthy and safety and fiscal soundness," he said.

Kizer said he accepted the position in 2006 with the assumption he'd hold it for approximately five years. In 2011, he applied for the position of city attorney in Henderson, Nev., and was named a finalist before it went to Josh M. Reid.

The No. 1 live gates in both boxing and mixed martial arts occurred during Kizer's service as executive director. The top grossing boxing event, a world title bout between Floyd Mayweather Jr. and Saul Alvarez at the MGM Grand Garden Arena, drew a reported $20.03 million in September.

Several key policy changes were implemented as well, including the use of instant replay and the growth of out-of-competition drug testing.

Kizer did receive worldwide criticism in 2012 for his selection and defense of boxing judge C.J. Ross, who along with Duane Ford, scored a WBO welterweight title fight for Timothy Bradley over Manny Pacquiao. Ross eventually resigned last year, after scoring the Mayweather-Alvarez fight a controversial draw.