Hong represented North Korea at the 2008 Summer Olympics in Beijing, where she won the gold medal in the women's vault competition.

Though she retained her full difficulties and performed impressively, she failed to defend her title and won a silver medal instead.

[5] In November 2010, Hong Su-jong was permanently banned from all international competition as a consequence of providing inconsistent age information.

North Korea was also banned from all international competition until October 2012 due to this incident, which most significantly included the 2012 Summer Olympics.

[6] Hong Un-jong has never been personally implicated in the age falsification, but the consequent country-wide ban meant that she could not defend her Olympic title on vault.