[3] After several extremely successful years in karting, Toyota signed Plowman to a 10-year contract to their young driver program.

In 2008 Plowman became an official Volkswagen junior driver where he was assigned to the newly re-formed RC Motorsport team and drove in the first seven rounds (14 races) of the Formula Three Euroseries where he failed to score any points and only managed a best finish of 17th.

In 2011 Plowman made his IndyCar Series debut with Sam Schmidt Motorsports as a part of their partnership with AFS Racing.

Plowman competed in the events at Mid-Ohio Sports Car Course, Infineon Raceway, and the Baltimore Grand Prix, driving the number 17 car featuring the logo of Snowball Express, a volunteer organisation created to assist the children of military personnel who have died while on active duty since the 9/11 attacks.

[4][5] [6] In each event, Plowman improved upon his starting position and upon his previous results, culminating in a near top-10 finish at the Baltimore Grand Prix.

[7] The team finished 3rd in the ALMS P2 class (44th overall), despite having to replace Dracone with Jan Heylen just 12 hours before the race due to illness.

[9] Plowman and Heinemeier Hansson achieved their first P2 class pole and victory (3rd place overall) at the Grand Prix of Mosport on 22 July 2012.

For 2013, Plowman and his Conquest co-driver Heinemeier Hansson were both hired by OAK Racing to drive Morgan-Nissans in the LMP2 class on the FIA World Endurance Championship.

[10] On the 6 Hours of Spa-Francorchamps, González, Baguette and Plowman finished in third position (for cars registered for points in the FIA World Endurance Championship), of LMP2 class (eleventh overall).

[11] In 2013 Plowman and his co-drivers Ricardo González and Bertrand Baguette from OAK Racing Morgan LMP2-Nissan team, won the 81st edition of the 24 Hours of Le Mans in LMP2 class (seventh overall).

The race was run in very difficult weather conditions and several serious accidents bringing out a record of twelve safety car caution periods.