As a junior player, Ong won the 2002 Asia Junior Championships gold medal in the boys' doubles event and bronze medal in the team event. At the World Junior Championships, he won the boy's doubles bronze. He also won the bronze medal at the 2005 Asia Championships. Together with Gan Teik Chai, he also won some international tournament in Mauritius, Argentinal and Brazil.
Ong played at the 2007 BWF World Championships in men's doubles with Tan Bin Shen. They were seeded #16 and were defeated in the first round by Tadashi Ohtsuka and Keita Masuda, of Japan, 21-14, 21-8.
Ong's partner changed to Hoon Thien How. They participated in Indonesia Open 2008 and did their best as they became the semi-finalist, beaten by Candra Wijaya and Tony Gunawan, 25-23, 15-21, 15-21. This unsatisfying result was continued as they lost to second-seeded Cai Yun/Fu Haifeng in China Masters 2008 15-21, 21-17, and 20-22.
In 2009, Ong and Hoon reached Yonex-Sunrise Vietnam Open final, but they lost to Indonesia's Luluk Hadiyanto and Joko Riyadi which were seeded 7 in straight sets, 19-21 and 20-22.
The BWF Grand Prix has two level such as Grand Prix and Grand Prix Gold. It is a series of badminton tournaments, sanctioned by Badminton World Federation (BWF) since 2007.
BWF Grand Prix Gold tournament
BWF Grand Prix tournament
BWF International Challenge tournament
BWF International Series tournament
BWF Future Series tournament