Czech Republic judoka Lukas Krpalek won gold in 2016, then moved up a weight class and did it again.
Krpalek held off the challenge of Georgia's Guram Tushishvili to claim the honors in Japan on Friday at Nippon Budokan.
Seeds Nos. 1 through 4 made the semifinals for the +100kg weight class in men's judo, but the top two fell to set up Nos. 3 and 4 for a gold medal match.
World No. 1 Tamerlan Bashaev of the Russian Olympic Committee and No. 2 Hisayoshi Harasawa of Japan were left to tangle for bronze medals after losing in semifinal clashes.
Bashaev won bronze by ippon in his match, but Harasawa was denied by two-time defending gold medalist judoka Teddy Riner of France.
No. 1 seed Idalys Ortiz of Cuba found out what many judokas are learning in Tokyo this summer, that beating Japanese athletes on home soil is a massive challenge.
Ortiz took silver in Rio and claims the same honor in Tokyo after falling to No. 3 seed Akira Sone on Friday.
The judokas to lose in the semifinal both rebounded to take bronze, as No. 2 Iryna Kindzerska of Azerbaijan shook off her loss to Sone and Romaine Dicko of France joined her on the podium.