New Japan Pro Wrestling (2002–2007)
Yamamoto trained for his professional wrestling career in the New Japan Pro Wrestling Dojo before making his professional wrestling debut on October 12, 2002.[3]
Yamamoto lost to Wataru Inoue in his debut match in the first match of a show in the Korakuen Hall.[4] Initially Yamamoto worked low card matches for NJPW, normally on the losing side to gain ring experience. On December 27, 2003, Yamamoto lost to Ryusuke Taguchi in a match where the winner would get a match on NJPW's most prestigious show, their January 4 Dome Show Wrestling World.[5] Yamamoto participated in the 2004 Young Lion Cup where he defeated Hirooki Goto, Aikya Anzawa, and Hiroshi Nagao to earn a total of six points, not enough to qualify for the finals.[6][7][8] Yamamoto also participated in the 2005 Young Lion Cup where he only won one match, defeating Yujiro.[9] In 2006 Yamamoto participated in his first G1 Climax tournament, losing all four matches.[10] Yamamoto teamed up with Manabu Nakanishi to compete in the 2006 G1 Climax Tag League, defeating Giant Bernard and Travis Tomko to earn their sole victory in the tournament.[11] On January 8, 2006, Yamamoto and Osamu Nishimura defated Toru Yano and a returning Togi Makabe.[12] Over the summer of 2007 Yamamoto began teaming regularly with Hiroshi Tanahashi forming a team called "New Japan Dragons", earning a match for the IWGP Tag Team Championship against the then champions, Bernard and Tomko, albeit in a losing effort.[13] For the 2007 G1 Climax Tag League Yamamoto teamed up with Takashi Ilzuka, while they defeated three teams (Hirooki Goto and Milano Collection A.T., Togi Makabe and Toru Yano, and Giant Bernard and Travis Tomko); the team ended up in last place.[14] On November 2, 2007 Yamamoto wrestled his last match for NJPW, teaming with his mentor Yuji Nagata in a losing effort against Tomohiro Ishii and Toru Yano.[15]

In late 2007 Yamamoto was signed by World Wrestling Entertainment (WWE) to a full time contract, which meant that he had to relocate to the United States. He immediately was assigned to WWE's developmental territory Florida Championship Wrestling (FCW), to undergo assessment and training in the "WWE Style" of wrestling. Initially he wrestled as Mr. Yamamoto, then simply as Yamamoto.[16] He briefly teamed with Sheamus O'Shaunessy under the team name "the Movers and the Shakers".[17] Later on he changed his ring name to Yoshitatsu, before tweaking the spelling to Yoshi Tatsu, the name he currently works under.[16]

On June 30, 2009, Yamamoto joined the ECW brand under the ring name Yoshi Tatsu. He had his first match that night, defeating Shelton Benjamin, although he lost a rematch to Benjamin on the July 9 episode of ECW.[18][19] On the October 20 episode of ECW, Tatsu defeated Zack Ryder to become number one contender for the ECW Championship, although he failed to win the championship the following week against Christian.[20] On the December 22 episode of ECW Yoshi Tatsu defeated Jack Swagger to earn a spot in the ECW Homecoming battle royal where the winner would challenge Christian for the ECW title at the Royal Rumble.[21] On the January 12 episode of ECW, however, Tatsu was not able to win the battle royal when he was eliminated by Kane. At the Royal Rumble Tatsu competed in his first Royal Rumble match, but was eliminated by John Cena.[22] Tatsu then formed a tag team with Goldust [23] and the duo became the number one contenders for the Unified WWE Tag Team Championship [24] but failed in capturing the titles on the final episode of ECW on Syfy.

After the ECW brand was discontinued, Tatsu made his debut on the Raw brand on the February 22, 2010 episode of Raw, where he teamed up with Evan Bourne and Kofi Kingston to defeat The Legacy (Randy Orton, Ted DiBiase, and Cody Rhodes), after Orton turned on his partners.[25] Tatsu won a 26-Man Battle Royal in the dark match to open WrestleMania XXVI by last eliminating Zack Ryder. In July 2010, Tatsu would be involved in a few backstage brawls with The Nexus to try to help John Cena get rid of them, which he failed to do. Yoshi then went to Japan to promote the new WWE SmackDown vs. Raw 2011 video game. After months of not appearing on WWE television, Tatsu returned on the November 11 episode of WWE Superstars, defeating Zack Ryder. On the November 29 episode of Raw, Tatsu teamed with Mark Henry to defeat WWE Tag Team Champions Justin Gabriel and Heath Slater, after a distraction by John Cena. A week later, Tatsu and Henry received a shot at the titles in a Fatal-4-Way Elimination Tag Team match, which also included The Usos and Santino Marella and Vladimir Kozlov. Tatsu and Henry were the first team eliminated in the match. On the February 14 episode of Raw, Maryse and DiBiase were about to kiss but instead Maryse kissed Tatsu. On the 24 February episode of Superstars during the match between Daniel Bryan and Ted DiBiase, Yoshi Tatsu came out and gave Maryse flowers but Maryse hit DiBiase with the flowers before Bryan used the LeBell Lock on DiBiase, making him tap out allowing Bryan to win the match. Tatsu also had a chance to earn a World Heavyweight Championship shot in a 20 man number one contenders battle royal which he was eliminated from.[26]

On April 26, Tatsu was drafted to the SmackDown brand as part of the 2011 Supplemental Draft.[27] His only appearances on SmackDown for 2011 were in the form of number one contenders battle royals for the World Heavyweight Championship and participation in the All I Want for Christmas battle royal where the winner would receive one wish.[26]
Tatsu was a WWE Pro for the fifth season of WWE NXT, also known as NXT Redemption, with his rookie being Byron Saxton. On the April 26 episode of WWE NXT, Tatsu was attacked by Saxton after Tatsu cost his match against Lucky Cannon. This would cause tension between the two until the May 17 episode of WWE NXT, where Tatsu would defeat Saxton. On the May 31 episode of WWE NXT, Saxton was the second rookie eliminated.
After Saxton's elimination, Tatsu began a feud with fellow NXT pro Tyson Kidd, whose rookie was also eliminated. Their feud stemmed from Kidd breaking Tatsu's toy figurine of himself and stealing one of the toy figurine's legs.[28] Both wrestlers would trade wins during their series of matches,[28][29] and Tatsu claimed back the stolen figurine leg by winning a Necklace on a Pole match on the July 26 episode of NXT.[30] After the match, Kidd brutally assaulted the right leg of Tatsu, causing Tatsu to be absent from NXT for more than a month. However, in the next few weeks, a mysterious Japanese symbol would appear on the TitanTron to distract Kidd during his matches. The symbol turned out to be the Kanji lettering for “pride” – a message from Tatsu. Tatsu returned on the September 6th episode of NXT, where he debuted black tights emblazoned with Kanji characters and the Japanese flag, had his small lock of blond hair dyed red and had half his face painted. Tatsu would go on to defeat Kidd on that episode to end the feud.[31] Tatsu later explained that his new look and wrestling style was due to him wanting to better portray Japanese culture, Japanese pride and the aggressive style of Japanese wrestling; he also explained that his face paint was a tribute to the Great Muta.[32] Tatsu stopped wearing his face paint to the ring by October 2011.[33]
Tatsu formed an alliance with Trent Barreta; from December 2011, they feuded with Curt Hawkins and Tyler Reks.[34] Both teams would play pranks on each other, with Tatsu being locked in a closet and Reks' hands being superglued onto an Xbox controller.[35] On January 18th Hawkins and Reks beat Barreta and Tatsu, culminating the feud.[26]
On January 24 Tatsu would team up with Santino Marella to form a comical, the pair could not decide what the tag team should be known as, Santino suggested "Santoshi" and Tatsu suggested "Yoshitino". The pair took on the WWE Tag Team Champions Primo & Epico in a losing effort.[26] On next weeks episode of SmackDown, Santino stated that the combination of the two was not suitable and therefore searched for another partner which would be Hacksaw Jim Duggan. Tatsu would then go on a losing streak against the likes of Jinder Mahal, Hunico, Damien Sandow, and Wade Barrett.[36][37][38][39] Tatsu would later lose to The Miz.