Kotani played a transvestite in TKO Hip Hop. Kotani portrayed Takashi Kawamura, the soft-spoken, dual-personality 3rd year regular of Seigaku Middle School's tennis club, in The Prince of Tennis musicals, Tenimyu. From 2005 to 2006, he was the fourth actor to play Kawamura as a member of the second-generation Seigaku cast. He made his debut as Kawamura on January 8, 2005 in the Side Yamabuki performance in Osaka. That same year, his role as Kawamura carried into the live adaptation film of the manga. On March 29, 2006, in the Dream Live 3rdLive concert, Kotani, along with the majority of the Seigaku cast, graduated from their roles. Kotani carried his role from the musicals to the live-adaptation film of The Prince of Tennis. He reprised his role in the movie. The Prince of Tennis was released on May 13, 2006 and opened in the tenth spot of the Japanese box office. Kotani starred in the made-for DVD release tokusatsu series, ZanSaber, as a tokusatsu hero. ZanSaber was released on November 18, 2006. Kotani's next project was filming for the made-for DVD release movie, Boys Love, which co-starred Saito Takumi. Kotani plays Mamiya Taishin, a magazine editor who meets high-school model, Kisaragi Noeru, during a magazine interview. Boys Love was released on November 24, 2006. In 2007, Kotani took the lead in the theatrical edition of Boys Love, which shared only its title with the 2006 movie, and featured a new story and cast. Kotani portrayed Aoi Kairu, a young teacher at an all-boys boarding school, who discovers that his new student, Amakami Sora is the boy with whom he recently had a sexual encounter. The movie costarred Yuuki Kawakubo and, in smaller roles, Toru Baba and Renn Kiriyama. In 2007, Kotani appeared in the film, Arakure KNIGHT, the live-action adaptation of the 1982 to 1988 manga series, Aratanaru Shobaku by Satosi Yoshida. The film was released in April 2007. Kotani acted alongside Yuu Shirota, Masaki Kaji, Kousuke Kujirai and Kenta Kamakari. Kotani is a member of +Plus, a J-pop band that does opening and ending songs for anime. Their latest anime was Hitman REBORN. +PLUS released four albums.
Personal life
Kotani began dating former Morning Musume member Risa Niigaki after they starred in the stage playAbsolute Boyfriend in 2013. After two years of dating, they married on July 11, 2016. On January 6, 2018, their blogs announced that they were filing for divorce.
Discography
2007 – "Going to the Road" was his first solo single, that also included "Irotodori no Sekai".
