Okabayashi is a former member of theJapan Self-Defense Forces and had a sports background injudo andweightlifting,[3][2] when he joinedBig Japan Pro Wrestling (BJW) in 2008 for a new career inprofessional wrestling.[4] He made his debut for the promotion against Katsumasa Inoue on June 27, 2008.[3][4] Okabayashi joined the promotion's non-deathmatch division, Strong BJ, eventually becoming one of its cornerstones alongside the likes ofDaisuke Sekimoto and Yoshihito Sasaki.[5] Four months after his debut, Okabayashi made hisAmerican debut, when he, along with several other BJW wrestlers, took part in the Global Gauntlet events held by theChikara promotion.[6][7]
The following year, Okabayashi and Sekimoto began making appearances forAll Japan Pro Wrestling (AJPW), where they won theAll Asia Tag Team Championship twice.[13] During the year, they also won the Big Japan Tag League.[14] At the end of the year,Tokyo Sports named Okabayashi and Sekimoto the 2011Tag Team of the Year.[15] During 2012, Okabayashi set his sights on theBJW World Strong Heavyweight Championship, a new title intended for the Strong BJ division.[16] He received his first shot at the title on June 21, but was defeated by Yoshihito Sasaki.[17] The following month, Okabayashi regained the BJW Tag Team Championship, this time teaming withShinobu.[18] After a four-month reign, they lost the title to Isami Kodaka andYuko Miyamoto in the finals of the 2012 Big Japan Tag League.[8] On March 31, 2013, Okabayashi received another shot at the BJW World Strong Heavyweight Championship, unsuccessfully challenging longtime tag team partner Daisuke Sekimoto.[19]
Okabayashi missed most of 2014 with a left shoulder injury, which he suffered while wrestling inGermany in January.[20] He returned from the injury on December 21.[21] His first big match since his return took place on February 2, 2015, when he unsuccessfully challengedShuji Ishikawa for the BJW World Strong Heavyweight Championship.[22] On February 15, Okabayashi and Sekimoto won another tag team title, when they defeatedKonosuke Takeshita andTetsuya Endo to win theDDT Pro-Wrestling promotion'sKO-D Tag Team Championship.[23] On July 20, Okabayashi scored his first-ever win over Sekimoto, when he defeated him to become the new BJW World Strong Heavyweight Champion, winning the first singles title of his professional wrestling career.[24][25] On August 23, Okabayashi and Sasaki lost the KO-D Tag Team Championship toDaisuke Sasaki andKota Ibushi.[26][27] On October 29, Okabayashi and Sekimoto defeatedKohei Sato and Shuji Ishikawa in the finals to win the 2015 Saikyo Tag League and the BJW Tag Team Championship.[28][29] They lost the title to Hideyoshi Kamitani andRyota Hama on December 30.[30] On June 8, 2016, Okabayashi won another tag team title, when he andYasufumi Nakanoue defeatedKazma Sakamoto andYuji Hino for theWrestle-1 Tag Team Championship.[31][32] A week later, Okabayashi and Daisuke Sekimoto defeatedBodyguard andZeus to win AJPW'sWorld Tag Team Championship.[33][34] On July 24, Okabayashi lost the BJW World Strong Heavyweight Championship to Hideyoshi Kamitani in his fourth defense.[35][36] On July 29, Okabayashi and Nakanoue lost the Wrestle-1 Tag Team Championship toJun Kasai andManabu Soya in their second defense.[37][38] On October 31, Okabayashi and Sekimoto defeated Isami Kodaka and Yuko Miyamoto to win their second Big Japan Saikyo Tag League in a row.[39] On November 27, Okabayashi and Sekimoto lost the AJPW World Tag Team Championship back to Bodyguard and Zeus.[40][41] On December 14, Okabayashi and Sekimoto won their second Tag Team of the Year award fromTokyo Sports.[42] On January 2, 2017, Okabayashi and Sekimoto defeated Kohei Sato and Shuji Ishikawa to win the BJW Tag Team Championship for the third time.[43][44] They lost the title toAbdullah Kobayashi andRyuji Ito in their fifth defense on July 17.[45][46] On August 27, Okabayashi and Sekimoto defeatedKai andNaoya Nomura to win thevacant AJPW World Tag Team Championship for the second time.[47][48] They relinquished the title on October 16 after Okabayashi suffered a shoulder injury.[49][50] It was later announced that Okabayashi would be undergoing surgery the following December, which would sideline him for up to a year.[51]
In October 2018, BJW announced that Okabayashi would be returning from injury atRyōgokutan 2018.[52] On November 11, he lost Ryuichi Kawakami in his return match.[53] On December 9, Okabayashi and Sekimoto unsuccessfully challengedRyota Hama andYasufumi Nakanoue for the BJW Tag Team Championship.[54] On January 13, 2019, they won the AJPW World Tag Team Championships for a third time, defeatingShuji Ishikawa andSuwama.[55] They defended their titles againstJake Lee andRyoji Sai on February 24[56] before losing the titles back to Ishikawa and Suwama on March 19.[57] In April, Okabayashi won a tournament to determine the number one contender for the BJW World Strong Heavyweight Championship by defeatingDaichi Hashimoto in the finals on April 14.[58] On May 5, for a second time, he defeated Sekimoto to win the BJW World Strong Heavyweight Championship.[59] He lost the title to Kohei Sato on August 25 after two title defences.[60] In November, he won the Zero1Furinkazan Tag Tournament withYuji Hino and the BJW Saikyo Tag League withShigehiro Irie.[61][62] On January 1, 2020, he unsuccessfully challenged Hino for theZero1 World Heavyweight Championship.[63] The following day, he also unsuccessfully challenged Daichi Hashimoto for the BJW World Strong Heavyweight Championship.[64] On January 13, he won the World Is Not Enough ~ Six Man Tag Team Tournament with Hino and Akira Hyodo. On March 3, Okabayashi and Irie unsuccessfully challenged Sekimoto and Sato for the BJW Tag Team Championship.[65] On March 25, he won the 2AW Openweight Championship from Shu Asakawa.[66] Also in March, Okabayashi had been entered into the2020 Ikkitousen Strong Climb as part of the C Block; however, due to theCOVID-19 pandemic, several events scheduled to showcase the Ikkitousen Strong Climb were cancelled and all remaining matches were adjudged as draws, causing Okabayashi to miss out on the finals. On July 5, he lost the 2AW Openweight Championship toAyato Yoshida.[67] On October 21, Okabayashi won his third BJW World Strong Heavyweight Championship by defeating Daichi Hashimoto.[68] He lost the title to Yasufumi Nakanoue on January 2.[69]
