Kim made her debut in the marathon in 2011, running at the Macau Marathon and finishing tenth with a time of 2:38:36 hours. Her run at the 2012 Pyongyang Marathon brought her up to the elite standard, as she won the race with a personal best of 2:30:41 hours. This run earned her a place on the North Korean team for the 2012 Summer Olympics, where she placed 74th overall in the women's Olympic marathon. A return to Pyongyang in 2013 saw her rise to the top of the national team with a second win at the race with a time of 2:26:32, ranking her third on the North Korean all-time lists.