As 1991 began, Mutoh was rapidly approaching the top of the promotion but still needed another bump to cement himself as the future of New Japan. In the summer of 1991, a new tournament called the G1 Climax gave Mutoh that opportunity. Set up as an eight man round robin tournament, it was a mixture of new stars and the old guard as Mutoh had Fujinami, Scott Norton, and Vader in his block. After losing to Norton, Mutoh picked up his first ever singles victories over Fujinami and Vader to reach the finals. Facing him would be none other then the man he debuted against, Masahiro Chono. Chono defeated Choshu in his half of the tournament, as New Japan was putting a real effort behind getting the new generation over. In the Finals, Chono and Mutoh would put on a match for the ages, in what many still consider among their best matches. Chono would win, but as the pillows rained down from Sumo Hall it was clear that two stars were born that day. The match also set the G1 Climax as a premiere tournament and it has remained one of the highlights of New Japan's year ever since.

Riding the wave from his success in the G1 Climax, in November Mutoh teamed with Hase to win the IWGP Heavyweight Tag Team Championship for the third time. At the Tokyo Dome in January of 1992, Mutoh would team with his old nemesis Sting to defeat The Steiner Brothers. On April 17th, 1992, Mutoh finally got a chance to win the IWGP Heavyweight Championship as he took on Riki Choshu, but he came up short. Mutoh wouldn't quit however, and in August he challenged Choshu again, this time as the Great Muta. Muta was too much for Choshu, who couldn't figure out Muta's unorthodox style, and Mutoh finally won the IWGP Heavyweight Championship, the first of the Three Musketeers to hold the belt. The Great Muta would hold the title for over a year, defeating the best New Japan had to offer (including Shinya Hashimoto, Masahiro Chono, and his "father" Great Kabuki). But it would be Hashimoto that would take him down, as in September of 1993 Muta was finally defeated in New Japan. During that run, Great Muta also had another special accomplishment as on January 4th, 1993 he defeated Masahiro Chono to win the NWA Heavyweight Championship. Mutoh (as Muta) would be the first wrestler to hold both the NWA Heavyweight Championship and the IWGP Heavyweight Championship at the same time. On top of that, Muta also battled then WWF Heavyweight Champion Hulk Hogan in May of 1993, showcasing himself as a global star that would take on all comers from any promotion.

Hashimoto proved to continue to be Mutoh's biggest rival, as Mutoh tried to immediately win back his IWGP Heavyweight Championship (as himself) but he was unable to win his title back. But Mutoh continued to excel in the tag team division, winning the Super Grade Tag League in both 1993 and 1994 with Hiroshi Hase. They would also win the IWGP Heavyweight Tag Team Championship again in November of 1994, the fourth time Mutoh had held the title. In the Spring of 1994, the great Antonio Inoki was in the midst of his retirement countdown and was growing increasingly disgusted with Great Muta's questionable tactics. So Inoki challenged Great Muta, with Muta accepting and the match took place in May. Muta gave Inoki everything and then some, but the old veteran squeaked out a victory with a sneak sleeper. As 1994 ended he was still the IWGP Heavyweight Tag Team Champion but he failed to win back the IWGP Heavyweight Championship and still had not won a G1 Climax.

All that changed in 1995, arguably the best year of Keiji Mutoh's career. After teaming with Hase at the Tokyo Dome to beat The Steiner Brothers, on May 3rd he got another chance at his biggest rival Shinya Hashimoto to re-claim the IWGP Heavyweight Championship. Wrestling as himself instead of his alter ego, Mutoh came up victorious and won the title for the second time. Over the course of the year he defeated the likes of Tenzan, Takada, and Koshinaka to keep the title through December. Also in 1995, Mutoh finally won the G1 Climax for the first time, as he defeated Ric Flair, Masahiro Chono, Scott Norton, and Hiroshi Hase on his way to winning the tournament. Holding New Japan's top title for the majority of the year and winning the premiere tournament, Mutoh temporarily surpassed his biggest rivals and was prepared to lead the promotion against the invading UWF-I.

This turned out to not be the case, as on January 4th, 1996 he lost his IWGP Heavyweight Championship to Nobuhiko Takada. Mutoh laid low for much of the spring (it would be Hashimoto that would win the title back for New Japan), but Mutoh entered the 1996 G1 Climax the defending winner and looking to win it again to get himself back to the top. The plan worked at first as he defeated Satoshi Kojima and Koshinaka, but he would be defeated by Masahiro Chono and Yamazaki, giving him his worst finish ever in the tournament. In October, the Great Muta went to WAR to challenge former foe Genichiro Tenryu, but Tenryu would come out victorious. Mutoh came close to winning the Tag League in December, but he and his partner Rick Steiner fell to Scott Norton and Shinya Hashimoto. As 1996 ended, from his two IWGP Heavyweight Championship runs totaling almost two years and his multiple IWGP Heavyweight Tag Team Championship runs, Mutoh had cemented himself as one of the main stars in the promotion, but he wasn't the "ace" as Chono and particularly Hashimoto stayed right with him each step of the way. With increasingly achy knees and frustration over not getting a IWGP Heavyweight Championship shot after losing it on 1/4/96, 1997 would bring a change for Mutoh as a new movement invaded New Japan Pro Wrestling.

Go to 1997-2001: nWo to Transformation