[10] That same year, Tajiri competed for New Japan Pro-Wrestling (NJPW), participating in the promotion's Best of the Super Juniors IV tournament as a guest from BJW.

On an episode of Monday Night Raw in July 1997, he lost to Taka Michinoku, whom the WWF was pushing as its rising star in the Light Heavyweight division at the time.

He made his television debut in ECW on the December 24, 1998, episode of Hardcore TV, clad in traditional blue and white trunks with an insignia of Japan's rising sun, and picked up a victory over Antifaz Del Norte.

His wrestling trunks were replaced with baggy Karate gi pants, and he began spraying green mist into the face of his opponents.

[18] Shortly after his alliance with Whipwreck, Tajiri's amusing antics in the ring, stiff contact with opponents, and comedic backstage vignettes made him one of the most popular wrestlers in ECW.

With the help of Regal, Tajiri made his in-ring debut defeating Crash in a King of the Ring 2001 qualifying match.

[25] Tajiri would quickly bounce back as he began an on-screen relationship with Torrie Wilson and defeated Chris Kanyon for the WCW United States Championship.

At SummerSlam, Tajiri competed in a Fatal four-way match for the WWE United States Championship but failed to win the title.

[36] Tajiri would successfully defend the championship in Mysterio's rematch at No Mercy after Akio and Sakoda, later known as "Kyo Dai", interfered in the match.

[40] Following WrestleMania XX, Tajiri was drafted to Raw, where he turned face once again and feuded with the group of Eric Bischoff, Jonathan Coachman, and Garrison Cade.

[41] On February 4, 2005, in Saitama Super Arena, Tajiri reunited with William Regal to defeat La Résistance for the World Tag Team Championship on an episode of Raw emanating from Japan.

Tajiri returned for a one-night appearance at WWE's ECW One Night Stand 2006 pay-per-view, teaming with Super Crazy to lose to The Full Blooded Italians (F.B.I.).

Tajiri's return to Japan came at Hustle on March 5, 2006, defeating Kohei Sato, The Monster PTA and Yoji Anjo with Razor Ramon Hard Gay and Shinjiro Otani.

[48] Tajiri was a title contender in All Japan Pro Wrestling throughout 2007, including a feud with Triple Crown Heavyweight Champion Minoru Suzuki.

[49] Tajiri returned to All Japan Pro Wrestling in 2011 to team up with Great Muta and Kenso in a loss to Partisan Forces (Masakatsu Funaki and Minoru Suzuki) and KAI.

[50] Tajiri would then bring Smash's biggest stars to AJPW for a one-night event where he and his partners Akira and StarBuck defeated Bushi, Keiji Muto, and Shuji Kondo.

[50] During the summer of 2009, Tajiri invaded NJPW, where he started a feud with the International Wrestling Gran Prix (IWGP) Heavyweight Champion Hiroshi Tanahashi, by attacking and green misting him after his title defense against Takashi Sugiura.

On August 13, Tajiri pinned the IWGP Heavyweight Champion in a non-title match during the G1 Climax tournament, after using the green mist.

[58][59] On June 19 at Dominion 6.19, Tajiri returned to New Japan, turning face and saving former rival Hiroshi Tanahashi from Toru Yano and Takashi Iizuka.

[67] On February 25, 2011, Tajiri gave Kushida his blessing to leave Smash and become a full-time member of the New Japan roster on April 1.

[70] On February 10, 2012, Smash announced that the promotion would be folding after its March 14 event, following a disagreement between Tajiri and financial backer Masakazu Sakai.

[80] Tajiri, Hajime Ohara, and Kana, the former partners of the three formed an alliance of their own to battle the three, but were on August 2 defeated in the first match between the two groups.

[81] Following the match, Ohara also turned on Tajiri and WNC, forming a new partnership with debuting female wrestler Nagisa Nozaki.

[82] On August 30, Tajiri teamed with Kana and the returning Mikey Whipwreck in a Barbed Wire Board Deathmatch, where they were defeated by Akira, StarBuck and Syuri.

[101] On May 16, 2015, Tajiri defeated Minoru Tanaka at a Wrestle-1 event to capture the European Wrestling Promotion (EWP) Intercontinental Championship.

[105] On June 19, Wrestle-1 announced a new contractual status for Tajiri, which would see him work only sporadic Wrestle-1 events from July onwards due to looking for a new career as an acupuncturist abroad.

[108] On July 29, Tajiri, Hayashi, and Tanaka lost the UWA World Trios Championship to Andy Wu, Daiki Inaba and Seiki Yoshioka in their fifth defense.

[107][109] Tajiri debuted at the August Impact Wrestling tapings in New York City, defeating Robbie E on August 5 (aired September 24),[110] and working matches on the August tapings; Tajiri and Austin Aries lost to James Storm and Sanada and then on the September 24 episode of Impact Wrestling, he competed in the NYC Gold Rush Final fatal five-way match which also included Abyss, Mr. Anderson, MVP and Austin Aries with Anderson winning the match.

[117] After weeks of recovery, Tajiri returned at a 205 Live taping in February, following a match between Lince Dorado and Brian Kendrick.

As the "Japanese Buzzsaw" Tajiri began to display a more ruthless, deranged persona, focusing more on inflicting pain on his opponents than winning matches, which included creating the Tarantula submission hold.