Reverting to his real name, he joined the
New Japan Pro-Wrestling (NJPW) promotion in June 1993, making his debut in February 1994. Even though he was a sumo wrestler before, he did not received the same usual special treatment that other sumo champions
Hiroshi Wajima in
All Japan and
Koji Kitao in New Japan received when both also started in professional wrestling. This was mostly because of the issues behind the reasons they joined the sport and how it end up bad for them, as Wajima used professional wrestling to settle his enormous gambling debts, and Kitao engaged in various confrontations with professional wrestling promoters due to being called out for his lazy habits and bad attitude. With that being said, New Japan made Yasuda start from the absolute bottom, presenting him as a young lion instead of a celebrity with past sumo champion status, a decision Yasuda humbly agreed upon. He spent the majority of the 1990s as an undercard wrestler, primarily competing in opening matches or as the fall guy in tag team matches with wrestlers such as
Shinya Hashimoto and
Kensuke Sasaki, achieving little success. In late 2000, Yasuda, along with
Kazuyuki Fujita, became somewhat of a pet project for
Antonio Inoki, and both of them were sent to the United States to train in
mixed martial arts. Yasuda returned to Japan soon after, and was victorious in his first fight against veteran
Masaaki Satake at
Pride 13. Yasuda's win helped further legitimise him as a pro wrestler in the eyes of Inoki, and this was rewarded with Yasuda reaching the semi-finals of the 2001
G1 Climax, where he lost to Keiji Mutoh. After earning one win and one loss in MMA throughout 2001, Yasuda earned the biggest win of his career in December by choking out veteran
Jerome Le Banner. His defeat of Jerome led to Yasuda's stock in New Japan skyrocketing almost overnight, and Yasuda soon found himself elevated from over the hill veteran to top title contender in early 2002. Yasuda earned the biggest win of his pro wrestling career on February 16, defeating Yuji Nagata in a tournament to win the vacant
IWGP Heavyweight Championship. Yasuda held the title for 48 days, before dropping it to Nagata in April. In August 2002, Yasuda and
Kantaro Hoshino formed their own faction, the
Makai Club, a group of wrestlers primarily with MMA backgrounds who worshipped Antonio Inoki like a god. Yasuda was viewed as the leader of the group, and in early 2003 he partnered up with his second in command
Kazunari Murakami to enter the
IWGP Tag Team Championship #1 Contender Tournament. Despite losing to
Jim Steele and
Mike Barton in the final, an injury to Steele would give the title shot to Murakami and Yasuda who unsuccessfully challenged
Hiroyoshi Tenzan and
Masahiro Chono on February 16. Having retired from MMA, the aging Yasuda's position in the New Japan card began to fall again, and in late 2004 he left the promotion. After leaving New Japan, he started making sporadic appearances for
ZERO-ONE and
Hustle. In October 2007 he reportedly attempted to commit suicide by carbon monoxide poisoning, using a
yeontan. A friend however, interrupted the alleged attempt. He was hospitalized with fears of possible
brain damage, but this proved not to be the case and he eventually made a return to wrestling. Speaking to
Tokyo Sports Yasuda later denied attempting suicide, saying the poisoning was accidental. On January 11, 2011, Yasuda announced his retirement from professional wrestling. He wrestled his final match on February 4, 2011, in which he was defeated by
Genichiro Tenryu. ==Mixed martial arts career==