The pre-competition build-up was dominated by talk of a duel between Kim and Chinese rival Zhang Jie, with the duo sparring for world titles over the last two years.
But Zhang was pushed into fourth place as in-form Oscar Albeiro Figueroa Mosquera, from Columbia, took silver ahead of Indonesia's Irawan Eko Yuli on a lighter bodyweight after tying with their final totals.
Kim followed up a snatch of 153kg, which broke the Olympic record and equalled the world best, with a clean and jerk of 174kg, providing him with a stunning personal best total of 327, which also eclipsed both records.
The Olympic record for clean and jerk also fell at ExCeL as Figueroa Mosquera lifted 177kg to help rack up a total of 317kg, level with Eko Yuli, who had to settle for bronze again after doing so four years ago.
Fourth-placed Zhang also saw his total world record sent crashing by rival Kim.