The fight lasted 4 minutes.
For the 25-year-old Russian, this is the first Olympic award in his career.
He has a silver and bronze medal at the 2019 and 2018 World Championships.
In another bout for the Olympic bronze medal in Tokyo, Portuguese Jorge Fonseca defeated Canadian Shady El Nahas.
Gold was won by the Japanese Aaron Wolf, who defeated the South Korean Cho Guham.
Earlier it was reported that Hamada became the Olympic champion in judo in the weight category up to 78 kg.