Ji Wallace won Australia's first Olympic gymnastics medal, in trampolining, at Sydney 2000. The gymnastics discipline made its Olympic debut at the Sydney Games, and Wallace was triumphant in front of a home crowd. After qualifying in equal third position, Wallace went on to claim the silver medal behind Alexandre Moskalenko, of Russia.
Wallace began trampolining in 1987 on the instruction of his mother who wanted the 10-year-old to learn danger avoidance. Wallace went to his first World Championships in 1992 and attended every championship after that in the lead up to the Sydney Games, with his biggest achievement coming when he won gold in the double mini trampoline in 1996. In the same event in 1998, Wallace set a world record, performing a triple front somersault with half twist into a back somersault with full twist.