Karun has excelled in every form of racing that he has contested in, starting by becoming the youngest Indian National Racing Champion in 2000. He achieved the impossible by not only being on pole position in all the 10 races but setting the fastest lap in every race as well, which is still a national record. He followed it up in 2001 by winning the opening 5 races of the season and a record 8 races to become the youngest Asian Formula Champion. He also tested with British Formula 3 champion team Carlin Motorsport at the end of the year.
The next 3 years saw Karun become a regular front runner in possibly the most competitive series in motorsport, the British Formula Three series; In his first year Karun finished 6th in the British Formula 3 National class with 6 top 3 finishes in the year. He followed it up by finishing an impressive 3rd in the British Formula 3 National class winning 8 races and scoring 19 podium finishes in 24 races with T-Sport. In 2004, Karun was a regular front runner in the British Formula 3 with T-Sport and was instantly a top 5 qualifier and finisher. He rounded off the year by partnering compatriot Narain Karthikeyan in the 'World Series by Nissan' for the final two rounds of the year.
The following year Karun was chosen to represent India in the inaugural A1 GP, a series where competitors represent their nation, rather than a private team which is the normally the case in racing. Karun also had the distinction of being the captain of Team India at the renowned 'Dubai 24hr' Kart race.
In 2006, Karun became the winner of the first ever Asian Formula Renault V6 Championship in dominating fashion by winning 7 out of 12 races, setting more records along the way. In 2007, Karun joined the GP2 series, the official support series for Formula One Championship, with Durango Racing. In probably the best win of his career, Karun sent a strong message to the motorsport world by winning the Belgian GP at the historic Spa-Francorrchamps circuit, resulting in the Indian National Anthem being played for the very first time at a Formula One Grand Prix event. Having caught the eye of leading Formula One teams, the dream became a reality when the Red Bull Racing team invited Karun to test their Formula One car in late 2007. Driving a Formula One car is the ultimate goal of any racing driver, which Karun managed to achieve at the age of just 24, becoming the youngest Indian to do so.
Karun continued to contest the GP2 Championship in 2008 with iSport International, partnering Bruno Senna. Karun added to his win tally at the German Grand Prix in the same year, together with podium finishes at the likes of Silverstone and Monaco. In the 2009 GP2 series, Karun joined newcomers Ocean Racing Technology and was enroute to winning the prestigious Monaco Grand Prix when a mechanical problem forced him to retire from the lead with 5 laps to go.
He has consistently proven to be the most successful Indian driver and has the distinction of being the only Indian driver to win 3 Championships, over 35 races, and start from the front row of the starting grid on over 25 occasions. While he has set the tone for motorsport in India, it is hard to believe that this youngster from Chennai has managed to achieve all this at the age of 26.
Karun has received many accolades in his career, being acknowledged and recognized by his peers, media and fans. He was the recipient of the Overdrive Magazine's 'Motorsport Man of the Year' in both 2002 and 2004, a feat accomplished by no other driver. In his first year of the GP2 Series in 2007, Karun was awarded 'Most Improved Driver of the Year' and followed it up next year by winning the award for the 'Best Driving Style' by the GP2 series. 2008 also saw him being the recipient of the Overdrive Magazine-Aaj Tak Motorsport award as well as the NDTV Profit – Car Magazine Motorsport awards. Karun also has the distinction of being India's first and only certified instructor at the Silverstone Racing School in England and for his achievements and contribution to motorsport, has become India's only member of the prestigious British Racing Driver's Club (BRDC).