Yu-Na Kim was born on September 5, 1990 in Gyounggi-Do, South Korea. She started skating in 1996 and currently trains with Brian Orser at the Toronto Cricket Skating and Curling Club in Toronto, Ontario. In 2003, Kim became the youngest South Korean Figure Skating Champion at the age of 12.
On her first trip to the World Junior Figure Skating Championships in 2004, Kim surprised everyone by winning the silver medal. In the 2005-2006 season, Kim remained as a junior skater as she was too young to compete at the 2006 Winter Olympic games. She won her two Junior Grand Prix Events and also won the 2005 Junior Grand Prix Final. She ended the season by winning the 2006 World Junior Figure Skating Championships. Kim made her senior international debut at the 2006 Skate Canada event winning the bronze medal. She won her first senior international title at the 2006 Trophée Eric Bombard and qualified her for the ISU Grand Prix Final. She won the 2006 Grand Prix Final during her first senior year. In March 2007, Kim competed at the World Championships in Tokyo where she set the world record for the highest short program score under the new ISU judging system. At her first appearance, Kim won the bronze medal. At the 2007 Cup of Russia event, Kim set the world recordfor the highest long program score under the new system. Kim proceeded to defend her title at the 2007 Grand Prix Final and ended the season by defending her bronze medal at the 2008 World Figure Skating Championships. At the 2009 Four Continents event, Kim set a new world record for her short program and won her first ever Four Continents Championships. At the 2009 World Figure Skating Championships, Kim once again set a new world record for her short program, beating her previous score by almost 4 points. This resulted in a total score of 207.71, a new world record for combined score and Kim became the first female skater under the new system to surpass 200 points. Kim is currently the 2009 World Champion and the 2009 Four Continents Champion.