After training in the Dramatic Dream Team dojo, Harashima made his professional wrestling debut in early 2001 as Konica Man and later became Hero!

[5] The storyline concluded in January 2003, when Hero!, supposedly on a business trip to Hong Kong, found Habukage disoriented and unable to remember anything from his past.

and Kudo ended the year by defeating Seiya Morohashi and Tomohiko Hashimoto, and Mikami and Onryo in a three-way Tables, Ladders, and Chairs match to win the KO-D Tag Team Championship.

entered the 2004 King of DDT tournament, beating one of the promotions' founder and top stars Sanshiro Takagi to make it to the finals, before losing to Poison Sawada Julie.

quickly bounced back in Big Japan Pro Wrestling (BJW), winning a One Night Six Man Tag Tournament with Jaki Numazawa and Super-X on June 13.

and Owashi defeated Seiya Morohashi and Thanomsak Toba to win the KO-D Tag Team Championship,[16] and lost the title's to Daichi Kakimoto and Kota Ibushi on November 23.

[19] In 2007, he defended his championship against Daichi Kakimoto on January 28, Danshoku Dino on February 25 and Sanshiro Takagi on April 1, before losing it to Koo on June 3.

[21] Calling themselves Jakai Tensho, they unsuccessfully challenged the Suicide Boyz (Mikami and Toba) for the KO-D Tag Team Championships on July 6.

[23] Harashima would reform Disaster-Box with Toru Owashi and on October 26, they won the KO-D Tag Team Championships by defeating Mikami and Thanomsak Toba.

[32] Harashima made two successful defence against Daisuke Sasaki on August 29 and Danshoku Dino on October 24, before losing the title to Hikaru Sato on November 14.

On December 26, Harashima, Owashi and Yukihiro Abe won the UWA World Trios Championship from Hikaru Sato, Michael Nakazawa and Tomomitsu Matsunaga.

[36] On April 6, during a four way match against Antonio Honda, DJ Nira and Michael Nakazawa, Harashima was attacked by the three other wrestlers before being saved by his alter ego Hero!.

[45] At Budokan Peter Pan: DDT 15th Anniversary, Harashima and NJPW's Togi Makabe defeated Shuji Ishikawa and BJW's Ryuji Ito.

[55] After four successful title defences, Harashima and Urano lost the KO-D Tag Team Championships to Hikaru Sato and Yukio Sakaguchi.

[58] On August 17, during the first day of DDT's 16th anniversary weekend at Ryōgoku Kokugikan, Urashimakudo lost to Team Dream Futures in a trios match.

[63] On November 4, Harashima continued his dominance, defeating Antonio Honda for the DDT Extreme Championship.,[64] becoming a triple crown champion in the process.

[70][71][72] In order to combat Kudo's new stable with Masa Takanashi and Yukio Sakaguchi, known as Shuten-dōji,[73][74] Harashima and Urano formed Smile Squash with Akito.

[76][77] Continuing into 2015, Harashima had made seven successful title defences before he lost the KO-D Openweight Championship to Kota Ibushi on February 15.

[85] On November 17, Harashima was able to gain a measure of revenge over Tanahashi by defeating him in a tag team match, pinning Yohei Komatsu.

[86] On December 31, Harashima teamed with Yuko Miyamoto to take part in the 3 Organization Shuffle Tag Tournament and reached the finals before losing to Daisuke Sekimoto and Konosuke Takeshita.

[89][90] After making his first successful defence against Kazusada Higuchi, Harashima lost his KO-D Openweight Championship when Daisuke Sasaki cashed in his "Right to Challenge Anytime, Anywhere" contract.

At Ryōgoku Peter Pan 2016, Smile Yankees defeated Kai and Ken Ohka to win the KO-D Tag Team Championships.

[93][94] On September 25, Smile Yankees defeated Damnation's Daisuke Sasaki and Tetsuya Endo to make their first successful title defense of the KO-D Tag Team Championships.

[105] At Judgement 2018: DDT 21st Anniversary, HarashiMarufuji lost their KO-D Tag Team Championship to Daisuke Sekimoto and Kazusada Higuchi.

[107] On May 8, following a disqualification victory against Tetsuya Endo, Harashima's last ally Soma Takao turned on him and joined Damnation, dissolving Smile Squash once and for all.

[108] Harashima won the DDT Extreme Championship for the third time, when he defeated Shinya Aoki, but on April 28, 2019, he lost his title to Antonio Honda in a bra match.