Simpson was born on 8 January 1984 in Poole, Dorset, England and he moved to South Africa with his family when he was 10 months old.

In 2001 Simpson left his native South Africa to compete in the Slick 50 Formula Ford Zetec Championship in the UK.

He ended the season with a stirring performance in atrocious conditions at Brands Hatch in the Formula Ford Festival.

For 2004 Simpson joined Richard Dean's Team JLR, with which he contested the prestigious British Formula Renault Championship.

Simpson was brought in to race in the inaugural A1 Grand Prix World Cup of Motorsport in winter 2005, helping A1 Team South Africa to a dismal 17th place in the series.

For 2018 he continues to race for JDC-Miller MotorSports in the top Prototype class of the IMSA Weathertech Championship alongside teammates Misha Goikhberg and Chris Miller in an Oreca Gibson LMP2 car, winning the 2018 Sahlens 6 Hours of the Glen at Watkins Glen.