Kim ran in the Pyongyang Marathon in 2006 and took third with a time of 2:29:25. She improved for the 2007 edition, setting a marathon personal best of 2:26:56 to take second place. She had her first success at collegiate level, winning the half marathon at the 2007 Summer Universiade. Having won at the age of eighteen, the win was North Korea's second ever title at the Universiade. She ran at the Beijing Marathon later that year and managed tenth place.