Ku represented South Korea in the men's team archery event and men's individual archery event at the 2016 Summer Olympics in Rio de Janeiro, Brazil. Ku and the South Korean team won the gold medal in the team event. Ku shot six consecutive perfect tens across three sets in the gold medal match against the United States. 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.