Unlike many racers Mardenborough can demonstrate no long -term experience in karting. While he drove between eight and eleven years on a kart track in Cardiff, where he grew up, but after closing the route lacked his family the financial resources to continue the hobby motor sport.
In 2011 he took part in the GT Academy, a competition from Nissan and Sony, which determines through virtual auto racing on the PlayStation a winner, the entry into the professional motorsport is possible. Mardenborough sat in this competition against 90,000 participants. As a premium title, he was employed at the 24 - hour race in Dubai from Nissan. He scored the third in his class. 2012 Mardenborough received a GT3 cockpit in the British GT Championship. Together with Alex Buncombe he won a race and finished in sixth place in the GT3 class. In addition, he participated in four races of the Blancpain Endurance Series.
2013 Nissan decided, Mardenborough use in Formula racing. First, he took part in New Zealand at the season of the Toyota Racing Series. As best rookie he finished the season on top of the tenth. Then Mardenborough received at Carlin a cockpit for the European Formula 3 Championship in 2013. He ran four times in the points and was at the end of the season as the worst Carlin driver on the 21st overall. In addition Mardenborough drove for Carlin in 2013 in the British Formula 3 Championship. With a second place as best result he finished sixth in the championship. In addition to its involvement in Formula Sports Mardenborough 2013 also took as part of the FIA World Endurance Championship ( WEC) in part for Greaves Motorsport at the 24 - hour race at Le Mans. Together with Michael Krumm and Lucas Ordoñez he reached the tenth and third in the LMP2 class. In addition Mardenborough 2013 came again in the Blancpain Endurance Series used and generated in two appearances a podium placement in its class.
Beginning of 2014 took Mardenborough again at the Toyota Racing Series part and started for Giles Motorsport. He won three races and was a total of seven times on the podium. With 782 to 790 points, he was at the end of the season runner-up behind Andrew Tang He subsequently received for the season of the GP3 Series a cockpit at Arden International. In addition, he was admitted to the funding of Red Bull.
Jann Mardenboroughs father Steve Mardenborough is a former English footballer.
- 2012: British GT Championship, GT3 ( 6th place)
- 2012: Blancpain Endurance Series, GT3 Pro-Am
- 2013: Toyota Racing Series (No. 10)
- 2013: European Formula 3 ( No. 21 )
- 2013: British Formula 3 ( 6th place)
- 2013: WEC LMP ( No. 32 )
- 2013: Blancpain Endurance Series, GT3 Pro-Am ( 14th)
- 2014: Toyota Racing Series (2nd place)
- 2014: GP3 Series