After impressing in pre-season trials with Sydney FC, including a goal against Manly United, he was announced as a new signing on 25 June 2009 for the upcoming 2009–10 season, on a two-year contract.

[3] Sydney FC released Byun at the end of the 2010–11 A-League season, deciding not to extend his contract for the Asian Champions League.

[4] After being released by Sydney, Byun entered into negotiations with fellow A-League club Newcastle Jets.

[6] Byun scored on his A-League debut for the Jets, sealing a 3–2 victory over Melbourne Heart in Newcastle.

[9] On 8 December 2011 the future of Byun was uncertain after routine medical tests revealed a potentially serious heart condition.