Yun Ok-Hui was first selected for the competitive South Korean national team in 2005. She claimed her first international medals at the Asian Championships, with silver individually and with the team. She improved on that performance at the 2006 Asian Games, with individual silver and a team gold. She also claimed the team title at the 2007 Asian Championships, finishing fifth individually. She qualified for the 2008 Olympics, where she went into the elimination phase as the second ranked archer. She was eliminated in the semi-finals by eventual champion Zhang Juanjuan, but bounced back to claim the bronze against North Korea’s Kwon Un-Sil. The South Korean women, with Yun, then proceeded to dominate the team event. After a world record in the ranking round, they easily won their quarter-final and semi-final matches. The gold medal round against China was a lot closer, though, and only decided with the final arrow (241-240). Yun made her World Championship début in 2009, finishing sixth in the individual event, but clamining gold with the team. She fared even better at the 2010 Asian Games, winning both available titles. She first ranked #1 in the world in July 2009, and held on to that ranking until April 2011.