In 2008 Summer Olympics she won the gold medal. She also won gold medals at the world championships of 2003, 2005, 2007, 2009 and 2011 as well as a bronze medal in 2001.
On May 10, 2010 she was banned for two years by the International Judo Federation because of Clenbuterol doping and was required to give back her gold medal from the World Championships of 2009. Tong subsequently contested the ban and took her case to the Court of Arbitration for Sport who ruled that a doping violation could not be proved and found in her favor ordering that she be reinstated immediately with all rights. She returned to international competition in May 2011 winning gold at the Moscow Grand Slam.