A native of Kent, Washington, Mayne is a former honorable mention junior college All-American quarterback in 1978 at Wenatchee Valley Community College in Wenatchee, WA. Kenny graduated from University of Nevada, Las Vegas in 1982, with a degree in Broadcasting, where he was the back-up quarterback and ahead of future NFL star Randall Cunningham on the depth chart. While at UNLV, Mayne played football for two years and later signed as a free agent with the Seattle Seahawks.

He has been the manager for the American League team in the Legends and Celebrity All Star Softball Game since its inception in 2001. In 2010, he chose not to appear in the game.

After beginning his television career with a brief stint as a reporter for KLVX-TV in Las Vegas, Nevada, Mayne spent seven years (1982-9) at KSTW-TV in Seattle, Washington. Eventually he became a weekend sports anchor and weekday news reporter. Mayne resigned from KSTW in 1989.

ESPN hired Mayne in 1994 after Mayne had sent ESPN a note inquiring whether the network would hire him. The note simply asked to check a box, including one option which read, "We'll hire you when there's an ESPN5."

Mayne started at ESPN in 1994 as a SportSmash anchor on ESPN2, and soon moved over to the main network. He became well known for his dry sense of humor and his unique home run calls.

For a time, he served as co-anchor of the 11PM SportsCenter with Dan Patrick after Keith Olbermann left ESPN. He left SportsCenter two years later, moving to an assortment of late night ESPN shows which were usually re-aired throughout the next morning. Included in his repertoire was the game show 2 Minute Drill. Mayne is now most often seen as the host for ABC and ESPN's horse racing events, as well as providing offbeat feature stories on Sunday NFL Countdown in a weekly segment called "The Mayne Event."

On January 17, 2007, ESPN signed Mayne to a one year contract to do features and cover horse racing, as well as return to SportsCenter for about 50 shows in 2007.[1]

Beginning October 2, 2008, Mayne starred in ESPN's first scripted web series, Mayne Street, playing a fictionalized version of himself.

Mayne doubles as an outfielder and on-the-field commentator annually in the Taco Bell All-Star Legends and Celebrity Softball Game, broadcast exclusively on ESPN.

In January 2006, Mayne participated in the second season of ABC's Dancing with the Stars with partner Andrea Hale, but after a disastrous cha-cha, Mayne was the first contestant to be eliminated in the first round. In an interview with Brian Falvey in the Spring of 2007, Mayne joked that he left the 2006 Rose Bowl at halftime in order to get up early the next day to practice for "Dancing with the Stars." Subsequent seasons have seen Mayne return to the show infrequently during the Results nights for "DanceCenter," a parody of SportsCenter alongside former contestant Jerry Rice and judge Len Goodman.

Mayne was also in the 1998 film BASEketball which featured the creators of South Park Trey Parker and Matt Stone. He was alongside Dan Patrick and appeared on SportsCenter to cover the latest BASEketball playoff competition.[2]

Before agreeing to the deal with ESPN, Mayne had talks with Comedy Central about doing a sports-themed The Daily Show-style program and was a finalist to be the host of the syndicated version of Deal or No Deal. He confirmed both discussions.[3]

Mayne has recently appeared in commercials for Progressive auto insurance, and Top Flite golf balls.

In November 2006, Mayne hosted the pilot episode of the CBS Primetime game show Power of 10 which would later be hosted by Drew Carey. Power of 10 producer Michael Davies was impressed with his performance on 2 Minute Drill, and wanted him to host one of his other game shows. After Mayne hosted the pilot, he decided to decline this hosting opportunity and it was given to Drew Carey.

In 2008 Mayne penned his first book, An Incomplete And Inaccurate History Of Sport, a collection of offbeat musings on sports and pop culture.

In 2010 he will appear in the animated film Kung Fu Magoo as himself.