The world champion's total of 700 points during the ranking round at the Sambodromo venue eclipsed the previous record of 699 set by compatriot Im Dong-hyun at the London Olympics four years ago.
Although he dazzled his Olympic rivals and thrilled the crowd in the terraces, the poker-faced Kim played down his achievement.
"Getting the world record is very important but tomorrow's matches are more important," the 24-year-old told reporters. "It's just the ranking round ... I want to focus on tomorrow, so today's not really big happy."