Glenn Jacobs, who wrestling fans will know better as Kane, won two-thirds of the vote in Knox County, beating Democrat Linda Haney.
The 51-year-old Republican ran on issues like keeping taxes low, improved infrastructure and “transparency”.
He is the second WWE star to win public office in the US.
Jesse Ventura was elected mayor of Brooklyn Park, Minnesota, in 1990, going on to be elected state governor in 1998.
Mr. Jacobs rose to fame in the mid-90s with his breakthrough character Kane, the masked half-brother of The Undertaker.
But despite Kane being described as “a monstrous abomination that seems to have been extracted directly from your childhood nightmares”, Mr. Jacobs believes his former career will be a help and not a hindrance.
“The thing someone like me brings to a race like this is, because of who I am, I can put Knox County in a positive light, nationally,” he told local news station WBIR. “There are so many great things our county has to offer, and frankly the rest of the country needs to know about it.”
Mr. Jacobs, who owns an insurance agency in Knoxville, will be sworn in as mayor on 1 September.
Source: BBC News