A former karateka and graduate of Koji Kitao's Bukō Dōjō, Masaaki spent the early part of his career wrestling for various promotions across Japan, namely WAR and BattlARTS.

In late 1999, Masaaki joined Toryumon, Último Dragón's upstart promotion, and quickly became recognized as one of the three "aces" of the company, alongside Cima, and Magnum Tokyo.

He returned in 2002, claiming to be a "good person", and made a conscious effort to rid M2K of its evil ways, something his stablemates would have none of; kicking him out of the group not long after.

On January 23, 2003, he formed the much-maligned Shin M2K, and they lasted until December 16 when he lost to fellow member Kenichiro Arai in a match and was forced to disband the unit.

When 2006 rolled around, he began to distance himself from Final M2K a bit, giving the reins of leadership to Susumu and joining up with Magnum Tokyo in his short-lived Renaissance project.

On January 14, 2007, the Final M2K stable came to an end, after he, Susumu & K-ness lost to Cima, Don Fujii and Matt Sydal of the also-ending Blood Generation.

On September 9, they won the Open the Triangle Gate Titles, defeating Naruki Doi, Masato Yoshino & Magnitude Kishiwada, and defended them right up until February 24, 2008, when they lost them to Shingo Takagi, BxB Hulk & Cyber Kong.

They faced off in a second round match in the King of Gate Tournament in December, where Mochizuki had promised that he would show Iwasa's one "fundamental flaw."

Mochizuki won, and afterwards, he told Iwasa that his "fundamental flaw" was that he had been a tag team wrestler for so long that he had forgotten how to wrestle on his own, and would have to re-learn how.

In August, he teamed with Katsuhiko Nakajima to participate in the annual Summer Adventure Tag League Tournament, and they made it to the finals, but they lost to Shingo Takagi & Yamato.

Two months later, he would hold the Triangle Gate titles for a third time, teaming with Don Fujii & Akebono to beat Masato Yoshino, BxB Hulk & PAC.

Mochi took the crown, and agreed the three would do the Royal Brothers (Anthony W. Mori, Henry III Sugawara, Phillip J. Mochizuki) on the first Buyuden after the generation war was over.

[4] On April 24 Mochizuki agreed to form a new alliance with former World-1 members Masato Yoshino, BxB Hulk, PAC and Susumu Yokosuka to battle the promotion's new top heel stable, Blood Warriors.

After a ten-month rivalry, Blood Warriors defeated Junction Three in a fourteen-man elimination tag team match on February 9, 2012, forcing JIII to disband.

He and Nagata took part in the round-robin portion of the 2012 World Tag League, finishing with a record of four wins and two losses, narrowly missing advancing to the semifinals of the tournament.