He made his international debut at the 2014 Archery World Cup after having participated in numerous Asian competitions prior.

Ku shot six consecutive perfect tens across three sets in the gold medal match against the United States.

[6] South Korea's victory against the United States marked the first time a South Korean archery team had beaten an archery team from the United States at the Olympics.

In the men's individual archery event, Ku defeated Frenchman Jean-Charles Valladont in the final to win his second Olympic gold medal.

This biographical article relating to a South Korean archery figure is a stub.