He will take charge of the Russian team until after the 2020 Olympic Games.
Rouhani, 36, won a gold medal at the 2006 World Championship in Tampere and also claimed a gold at the 2006 Asian Games in Doha.
Karate will make its debut appearance at the Summer Olympics in 2020 in Tokyo, Japan.
Olympic karate will feature two events, Kumite and Kata. Sixty competitors from around the world will compete in the Kumite competition and twenty will compete in the Kata competition.