ORLANDO, Fla. -- Orange County Sheriff Jerry Demings officially announced his resignation Thursday as part of his run for county mayor.

Demings turned in his resignation letter at the county Supervisor of Elections Office Thursday afternoon. His resignation will be official Dec. 4, which means Demings will remain the sheriff until then, but he won't finish out his four-year term, which is up in 2020, even if he loses the race for mayor.

Per state law, an elected official who is running for another office must resign no later than 10 days before the qualifying period begins for that election. In this case, the qualifying period begins noon, June 18.

"It's bittersweet, because after 30 years of being a law enforcement officer in this community, I've seen it through the best of times and the worst of times," Demings said. "So I'm just looking to continue my public service, really in a different office."

Demings says as sheriff he's reduced crime by 30 percent, been fiscally conservative – saving millions of dollars of taxpayer's money -- reduced the use of force against people and reduced the number of complaints against deputies.

"I'll miss the interaction with the brave souls, the men and women who go out and protect this community everyday – sometimes at a great sacrifice," said Demings.

Current Orange County Mayor Teresa Jacobs cannot run again because of term limits.

Demings, who is married to Democratic U.S. Rep. Val Demings of Orlando, is serving his third term as Orange County sheriff. He previously served as the county's public safety officer and was the Orlando Police Department's first black police chief.

The other candidates who intend to run for Orange County mayor are Pete Clarke, Jose Datil Colom, Robert Edward Melanson, Rob Panepinto and David Quiros.

A special election will be held for Orange County sheriff to serve out Demings' term.

While Demings hasn't endorsed anyone, he did talk about what kind of person he'd like to see take his current job.

"I want it to be someone who's immensely talented, to be able to come in and take over a very complex operation that will keep the people safe and treat them with dignity and respect," said Demings.

Orlando Police Chief John Mina filed paperwork in February to run for Orange County sheriff. Two other men have announced plans to run for Orange County sheriff -- Jose Lopez and Eric McIntyre.

The primary election is Aug. 28, and the general election is Nov. 6.

Reporter Jeff Allen contributed to this story.