[3] Yun signed for Queens Park Rangers on the 30 January 2013 for an undisclosed fee on a three-and-a-half-year deal.

However, he was included in the match day squad as a substitute for the first game of the 2013–14 Championship season before making his first league start of the campaign the next week in the away trip to Huddersfield Town, where he provided the assist for Junior Hoilett's equalising goal.

Away to Sheffield Wednesday on 18 March 2014, Yun came on as a substitute for Hoilett at half-time to cover the defence after Richard Dunne had been sent off.

Yun missed most of the season due to injury, making six appearances in total, as Busan were relegated to K League 2.

Yun played at Under 17 and Under 20 before appearing for the South Korea senior team on 16 October 2009 against Iran in a World Cup qualifier.