Ko represented her nation at international competitions. She participated at Asian Speed Skating Championships, winning the silver medal in 1994 and 1995 in the 5000 metres event and finished in the 3000 metres 4th (1994) and 5th (1995) and in the 1500 metres 7th (1994). She also competed at other international competitions, including at ISU Speed Skating World Cups. She competed at the 1996 Asian Winter Games and 1999 Asian Winter Games. She also competed in Canada and Germany.