James Dominic Grunwell was born on 4 February 1989. He has lived most of his life in Thailand.
In 2003, Grunwell entered his first official race with the newly formed Champion Racing Team, supported by Champion Ferodo. That year, he won the Thailand Under 18 100cc Veloil Challenge championship. He also competed in the Thailand Nationals in the Yamaha class, winning two of four races and achieving podium finishes in the remaining two. Grunwell continued karting with the 2003 kart, finishing fourth in the internationally recognized Intercon ‘A’ Class, and securing podium finishes in every race he entered.
Towards the end of 2004, Grunwell tested with AIM Racing, a leading Thai racing team, and was the fastest rookie ever to pass the test. He participated as a guest driver in the last two races of 2004, driving a Thai-built car with a 1600cc Toyota racing engine capable of speeds up to 160 km/h. In four of six races in the following season, he achieved two first-place finishes and additional podiums.
In 2005, Grunwell participated in the Formula BMW scholarship programme but missed out on the scholarship by one place. He then concentrated on karting in Thailand, winning all races in the Thailand Rotax Max Junior series. He competed in the World Finals in Langkawi for Rotax Max, finishing in the top-five in all races and starting fourth on the grid in the final, becoming the highest-placed Thai driver ever in the event.
Grunwell again joined the Formula BMW Asia scholarship program at the end of 2005, passing with “flying colors” and winning one of four BMW Scholarship prizes worth USD 50,000, along with bonus points for the fastest lap among 20 competitors. In 2006, Meritus Racing Team signed Grunwell as a Rookie driver for the Formula BMW Asia series, where he finished third in the Rookie Championship and fourth overall.
In 2007, Grunwell spent a second year in Formula BMW Asia with Meritus Racing Team, finishing third in points with three wins and twelve podium finishes. He then raced in Formula V6 Asia for Team Meritus in 2008, winning the championship with four wins and podium finishes in all but two of the twelve races.
In December 2004, Grunwell was invited for a test drive in a Formula BMW with the Meritus Racing Team in Malaysia, which he passed, leading to a drive with them in 2005.
Throughout 2005 and 2006, Grunwell was featured in numerous magazines and newspapers. He appeared with his Concept Car at the Bangkok 7th Rugby Tournament on behalf of his sponsor Champion Ferodo, performing a demonstration drive and presenting prizes. In 2007, The Pizza Company became a main sponsor, followed by Comcon Services Thailand and Image Makers Asia, with Grunwell actively promoting these companies in Thailand and abroad. According to a January 28, 2006 article by Mark Boudreau, Grunwell was considered an F1 prospect.
Despite his success in 2008, Grunwell has not participated in a professional motor race since that time.