He is a participant at the 2014 Winter Olympics in Sochi. Yun made his international debut in the 2012-2013 season, appearing at the North American Cup Tour. Yun first garnered attention in the 2013-2014 season when he was ranked fifth overall at the 2013-2014 FIBT Intercontinental Cup Tour.
Yun started skeleton at the age of 18 in early 2012, and after three-month training he won the national championship in September 2012. He won gold in the sixth round of the tour in Whistler, Canada on January 5–6, 2014, becoming the first Korean skeleton slider to finish on top of the podium at an international event.
