"I am determined to lead the sport in Japan. I hope the national team will move up one spot at a time in the world rankings, as Japanese rugby undergoes a baptism of fire at the professional level," Mori, capped 27 times by Japan, was quoted as saying by Kyodo News Agency.
"I hope that in a few decades from now, the Japanese national team will compete for victory against powerhouses at a World Cup held again in Japan."
The JRFU had been in turmoil since honorary president Yoshiro Mori resigned in April, calling for urgent reforms within the governing body.
Japanese Rugby also suffered a blow when Tokyo-based Sunwolves were axed from Super Rugby after the next season as the JRFU could no longer "financially underwrite" the team's participation.
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As part of an administrative overhaul, the JRFU also confirmed men's sevens coach Kensuke Iwabuchi as its new chairman.
"We have to work hard with the belief that what we do in the next year or two will decide the next 50 years of Japanese rugby," Iwabuchi said.
(Reporting by Hardik Vyas in Bengaluru, editing by Nick Mulvenney)
