Watts began his motorsport career in 1993 in karting, where he was active until 1997. In 1998 he moved to Formula racing and immediately won the champion of the British Formula First. He then took part in the Winter Series of Formula Palmer Audi and finished third. In 1999, he contested the Formula Palmer Audi season in and closed the standings to 22 overall from. In 2000 he moved to Manor Motorsport in the British Formula Renault. While his team-mate Kimi Raikkonen dominant won the championship title, Watts was a victory in tenth place overall. He also appeared in the Formula Renault 2.0 Eurocup and finished 16th in the championship. After Watts had become 2001, Falcon Motorsports third in the British Formula Renault, he won in 2002 for Fortec Motorsport the championship ahead of his teammate Jamie Green. He also participated in this year's ever a race in the Formula Renault 2.0 Eurocup and partly in the British Porsche Carrera Cup.
In 2003, Watts to Hitech Racing in the British Formula 3 Championship. With a win, he joined the championship from fifth place. In 2004, he played his second season in the British Formula 3 Championship for Promatecme. He decided once again a race for himself and finished sixth overall. He also appeared in the Japanese Formula 3 Championship and was 15th in this series. 2005 Watts found no cockpit for a full season and he started to two per race in the British Formula 3 and the World Series by Renault. In the British Formula 3 Championship, he scored a podium placement with a second place. He also took part in a race weekend of the Formula 3 Euro Series as a guest.
2006 Watts left the Formula racing and put his main focus on the British Porsche Carrera Cup where he finished third. He also took part in a race of the Porsche Supercup. In addition, he appeared as a guest starter to ever a race of the British Formula 3 and the Asian Porsche Carrera Cup and came in two races as the finish line first. 2007 Watts moved into the Le Mans Series ( LMS) and was 19th in the LMGT2 rating. In addition, he made his debut at the 24 Hours of Le Mans and in the American Le Mans Series ( ALMS). 2008 Watts took part mainly in the Porsche Supercup and finished ninth overall. In addition, he started at a ALMS race.
In winter 2008/2009 Watts returned for a commitment in the A1GP into formula racing. After six races in which he had become third twice, he moved again in 2009 in the Le Mans Series. He completed the season in 16th place from the LMP1 championship. In addition, he again took part in the 24 - hour race at Le Mans. Watts in 2010 competed in the LMP2 championship of the Le Mans Series. He won three times and was also read along with Jonny Kane and Nick Leventis runner-up in the LMP2 standings. In addition, the three pilots won the LMP2 classification in the 24- hour race at Le Mans.
- 2002: Formula Renault 2.0 Eurocup
- 2002: British Porsche Carrera Cup
- 2003: British Formula 3 ( 5th place)
- 2004: British Formula 3 ( 6th place)
- 2004: Japanese Formula 3 ( 15th place)
- 2005: British Formula 3 ( 13th place)
- 2005: World Series by Renault ( No. 32 )
- 2006: British Porsche Carrera Cup ( 3rd place)
- 2006: Porsche Supercup
- 2007: LMS, LMGT2 ( 19th place )
- 2007: ALMS LMP2 ( 16th place)
- 2008: Porsche Supercup ( 9th place)
- 2008: ALMS, LMP1 ( 14th)
- 2009: A1GP
- 2009: LMS, LMP1 ( 16th place)
- 2010: LMS LMP2 (2nd place)