Thong raced in the 2012 Asian Formula Renault Challenge with Formula Racing Development Limited, winning 1 race and with 2 podium finishes. Thong finished 3rd in his debut year of single seater championship. Apart from Asian Formula Renault Challenge, Thong also participated in the final round of the Maserati Trofeo MC World Series and finished 6th and was awarded for "The Best Asian Driver".Thong also participated in the Malaysia Super Series GT Open Class with 2 podium finishes. Apart from car racing Thong also entered the final round of the CIK-FIA KF-1 World Championship held in Macau after finishing 2nd overall in the Hong Kong Kart Club 125cc Class C with 2 wins and 2 other podium finishes.
2013
Thong joined Fortec Motorsports squad to race in the Protyre Formula Renault Championship in 2013 and secured 1 pole position and 1 fastest lap in the final round held in Silverstone. Despite finishing 16th in the championship, Thong showed strong potential by constantly qualifying in top 3 in 2013. Thong also made his debut in the 3rd round of Asian Le Mans Series in Zhuhai and won the overall and LMP2 class with OAK Racing in a Morgan / Judd LMP2 prototype. He also made an appearance in the round 7 and 8 Audi R8 LMS Cup as guest driver and finished 5th in round 8 on his debut for the championship. Thong also finished 3rd in his debut visit to the Macau Grand Prix, racing in the Formula Masters China - Macau Grand Prix Invitational race 2013 with Eurasia Motorsports.
2014
Thong joined Team West-Tec for the 2014 Euroformula Open Championship and won the Winter Series which was held in Paul Ricard, having to qualified on pole position and securing a race win with a fastest lap in the Copa Class Dallara F308 / Toyota. Thong graduated to the main class for the season driving the Dallara F312 / Toyota with Team West-Tec.
2015
In 2015 Thong was signed by Audi Sport Customer Racing Asia to be their first young driver development program talent and aim to promote young drivers to GT Racing. Thong participated in Various championship including the inaugural season of the Audi Sport TT Cup, having 1 win and 2 pole positions in Round 2 held in Nourisring. Blancpain Endurance Series driving the Audi R8 LMS Ultra for Phoenix Racing alongside Marchy Lee and Markus Winkelhock. Thong is also one of the drivers among the Audi Customer Racing Asia lineup that participated the 2015 24 Hours Nürburgring under a full Asian lineup for the first time, with Cheng Congfu, Marchy Lee and Alex Yoong completing the lineup. The full Asian team finishing 12th overall in the team's debut.
