At the 2008 Summer Olympics, he won the bronze medal in the individual event, the only trampoline event at the Olympics. His final score was 40.600.[2]
In 2018, he was first individually and in synchro at the Brescia World Cup. At the Maebashi World Cup, he was first in synchro; at the Loule World Cup he was fourth individually and fifth in synchro.[2] At the 2018 World Championships, he won individual silver with a score of 61.185. He ranked fifth in men's synchro and first in the team all-around.
At the 2019 Baku World Cup, Dong was second individually. At the World Championships he won individual bronze and team silver.
At the 2020 Baku World Cup, Dong won individual bronze.[2]