In November 1999, during his sophomore year in high school, he was at the forefront of 50 bōsōzoku groups in the "1999 Ebisu-ko Violence Incident", which was widely covered by the mass media nationwide, and was arrested and detained by the riot police.

Miyamoto would go on to make five successful defenses with the belt defeating Masashi Takeda, Abdullah Kobayashi, Mad Man Pondo, Takashi Sasaki and Isami Kodaka before losing it to Ryuji Ito on May 4, 2010.

[6] On March 29, 2012, Miyamoto defeated his partner Isami Kodaka to win the DDT Extreme Championship as part of an interpromotional rivalry between Union Pro and BJW.

[9][10] On May 31 Yankee Nichokenju lost the BJW Tag Team Championship to Twin Towers (Kohei Sato and Shuji Ishikawa), ending their eighteen-month reign at seventeen successful title defenses.

On November 21, Yankee Nichokenju defeated Abdullah Kobayashi and Ryuji Ito in the finals to win their third Dai Nihon Saikyo Tag League in a row.

[12][13] On December 31, Yankee Nichokenju took part in Toshikoshi Puroresu, an annual new year's collaboration event between BJW, DDT and Kaientai Dojo, winning the Tenka Toitsu!

[26][27] On September 25, Smile Yankees defeated Daisuke Sasaki and Tetsuya Endo to make their first successful title defense of the KO-D Tag Team Championship.

[29] In October 2015, Yankee Nichokenju took part in All Japan Pro Wrestling (AJPW)'s Jr. Tag Battle of Glory, where they finished second with a record of two wins, one draw and one loss, suffered against Atsushi Aoki and Hikaru Sato in their last round-robin match, the de facto final of the tournament.

[30][31] On November 15, Kodaka and Miyamoto defeated Kotaro Suzuki and Yohei Nakajima in a decision match to win the vacant All Asia Tag Team Championship.

After six successful title defenses, Miyamoto and Kodaka lost the All Asia Tag Team Championship to Atsushi Aoki and Hikaru Sato on July 24 at a BJW event.

[35] On August 24, Yankee Nichokenju lost the Wave Tag Team Championship to Sakuragohan (Kyusei Sakura Hirota and Mika Iida) in a three-way match, which also included Las Aventureras.