The 34 year old was riding the Moto Breakers Kawasaki ZX-10R and is believed to have made contact with another rider on the mountain section of the course.
The Sheffield rider had enjoyed a long and successful racing career having exploded onto the scene way back in 1999 when he won the European Superstock Championship onboard a Suzuki GSXR750. His victory propelled him into the spotlight and after a year in BSB he then switched to British Supersport where he won the championship onboard a GSXR600. He went on to win the Supersport title two more times riding for the HM Plant Honda team.
Harris also spent a large part of his career competing in BSB and despite coming incredibly close on numerous occasions he never actually won a race. His best season came in 2006 when he finished fifth in the overall standings behind Ryuichi Kiyonari, Leon Haslam, Gregorio Lavilla and Jonathan Rea. Shane Byrne was one place behind Harris in sixth.
In more recent years Harris continued to make selected appearances within the British Championship and in 2012 he made his TT debut onboard the SMT Honda posting a lap time in excess of 121mph.
Karl attended our BikeWise show in 2005 & 2006 whilst riding for HM Plant Honda.
A statement from race organisers reads:
ACU Events Ltd regrets to announce that Karl Harris, 34, from Sheffield was killed during the Superstock Race at the Isle of Man TT races today following an incident at Joey's on the second lap of the race.
Harris, a professional motorbike racer, made his TT Races debut in 2012. He was a triple British Supersport Champion and British Superbike podium finisher.
Harris appeared on the racing scene as a teenager in the 1990s, when he rode for Team Great Britain in the Superteen Championship. From there, Harris went on to win the 1999 European Superstock 1000cc Championship before spending a season in the World Supersport Championship.
He was best known for his British Championship career. He was the dominant force in the British Supersport Championship in the early 2000s before becoming a prominent front-runner in the Superbike class for the factory Suzuki, Honda and Yamaha teams.
Harris won three British Supersport Championships between 2001 and 2004, the first for Crescent Suzuki and the remaining two for Honda Racing, before progressing full time to the premier Superbike category in 2005. His best season came in 2006 when he finished in 5th place overall recording 6 podiums. In total, Harris notched up 12 BSB podiums.
The ACU wishes to pass on their deepest sympathy to Karl's family and friends.
Gary Thompson, TT Clerk of the Course, ACU Events, said: "Karl was one of the great characters in the race paddock. His infectious enthusiasm and sense of humour lit up many race meetings. He was a hugely talented racer and will be sorely missed."
The Coroner of Inquests has been informed and an investigation into the circumstances of the accident is underway.