She began competing as a junior athlete in 2000 and made her breakthrough in 2004 at the age of eighteen by setting a national record of 3.82 metres to win at the Korean National Sports Festival. She retained her title the following year and also made her first international appearances for her country, coming fifth at the 2005 East Asian Games and fourth at the 2005 Asian Athletics Championships in a new record 4.05 m (becoming the first Korean woman over four metres). She added a further five centimetres to her best mark to win at the 2006 National Festival and went on to finish fifth at the 2006 Asian Games.