Mitsuo Yamaguchi (山口 光雄, Yamaguchi Mitsuo), better known by his stage name of Kappei Yamaguchi (山口 勝平, Yamaguchi Kappei) is a Japanese voice actor and actor from Fukuoka, affiliated with Gokū and 21st Century Fox. He is best known for the roles of Ranma Saotome (Ranma ½), Jackson Neil (Miracle Girls), Tombo (Kiki's Delivery Service), Yattaro (Kyattou Ninden Teyandee), InuYasha (InuYasha), Ryuichi Sakuma (Gravitation), L (Death Note), Usopp (One Piece), Hideyoshi (Law of Ueki), and Kaito Kid and Shinichi Kudo (Case Closed). His current starring roles include that of Raimon "Monta" Taro, the Deimon Devil Bats' ace receiver in Eyeshield 21.
Yamaguchi has appeared in eroge as Kyōya Ushihisa (牛久 京也, Ushihisa Kyōya). He made his first public appearance in North America at Otakon 2008; and was also a guest at Sakura-Con 2009. Yamaguchi's third appearance to date has been at Animazement in 2010.
He is married and has a daughter, Akane Yamaguchi (山口 茜), and a son, Ryunosuke Yamaguchi (山口 竜之介), who also are voice actors.
Description above from the Wikipedia article Kappei Yamaguchi, licensed under CC-BY-SA, full list of contributors on Wikipedia.
as Momoyama Kyūsai (voice)(1 ep)
as Shinichi Kudo (voice)
as Usopp
as Shinichi Kudou (voice)
as Futoshi (voice)
as Inorin (voice)
as Vivace (voice)(11 eps)
as Carl Ojisan (voice)(12 eps)
as Shinichi Kudo (voice)
as The White Rabit (voice)
as Shinichi Kudo (voice)
as Usopp(21 eps)
as Usopp
as Ranma Saotome (voice)(36 eps)
as Yakumo (voice)(12 eps)
as Kaito Kid / Shinichi Kudou (voice)
as Shizuru's father (voice)(1 ep)
as Ticket (voice)(1 ep)
as Komao (voice)(12 eps)
as Kaito Kuroba / Kaito Kid (voice)
as Shinichi Kudou (voice)
as Kaito Kuroba (voice)
as Saizo (voice)(1 ep)
as Tsuyuo (voice)(3 eps)
as B-Bo (voice)(1 ep)
as Usopp (voice)
as Shinichi Kudo (voice)
as "Cute" Voiceover of the Week (voice)(1 ep)
as Mikhail (voice)(12 eps)
as Eiji Kakihana (voice)
as Comédien de doublage de Usopp – Japon
as Oberon (voice)(3 eps)
as Shinichi Kudo (voice)
as Jii-chan (voice)(64 eps)
as Eiji Kakihana (voice)(13 eps)
as 配音(18 eps)
as Bigbird Aragaki (voice)(11 eps)
as Kechizu (voice)(4 eps)
as Inuyasha (voice)(15 eps)
as Shin (voice)(24 eps)
as Shinichi Kudo (voice)
as ToQger Arsenal (voice)
as Jabbathe (voice)(1 ep)
as Shinichi Kudo / Kaito Kuroba (voice)
as ToQger Arsenal (voice)(4 eps)
as Usopp (voice)
as Master Lord Majesty (voice)(21 eps)
as Garizo (voice)
as Usopp (voice)
as Fu (voice)(54 eps)
as Shinpachi Nagakura (voice)
as Shinichi Kudo / Kaito Kid (voice)
as Ittan Momen(97 eps)
as Mucha (voice)
as Oberon (voice)(4 eps)
as Usopp (voice)
as Shinichi Kudo (voice)
as Pepu (voice)(12 eps)
as Sora Hiroi (voice)
as Shinichi Kudo (voice)
as Usopp (voice)
as Usopp (voice)
as Usopp (voice)
as Usopp (voice)
as Usopp(9 eps)
as Shinichi Kudo (voice)
as Illusion (voice)(1 ep)
as Ticket (voice), ToQger Equipment Voice
as Amaken (voice)(25 eps)
as Usopp (voice)
as Teenage Jiromaru (voice)
as Shitai-kun (voice)(11 eps)
as Ticket / ToQger Equipment Voice (voice)
as Ticket (voice)
as Zesta (voice)
as Shinichi Kudo / Kaitou Kid (voice)
as Sabato Rokudou(25 eps)
as Shinichi Kudo (voice)
as Ticket (voice)
as Michael (voice)
as Kaito Kuroba / Shinichi Kudo (voice)(24 eps)
as Osafune Kenny Eitarou(12 eps)
as Ticket / ToQger Equipment / Narrator (voice)
as Teddie (voice)(12 eps)
as Valefor (voice)(5 eps)
as Shinichi Kudo (voice)
as Tsukasa Mendō (voice)(32 eps)
as Ticket / ToQger Equipment (voice)
as ToQger Equipment Voice
as Ticket (voice)(47 eps)
as ToQger equipment (voice)
as Shinichi Kudo / Kaito Kuroba (voice)
as Usopp (voice)
as Hifumi Yamada (voice)(2 eps)
as Shinichi Kudo (voice)
as Garizo (voice)
as Garizo (voice)
as Feitan (voice)
as Usopp (voice)
as Usopp (voice)
as Usopp (voice)
as Shigechi (voice)(4 eps)
as Yo-Yo Ma(3 eps)
as Robin Baxter (voice)
as Kuma (voice)
as Kuma (voice)
as Shinichi Kudo (voice)
as Chief Editor HVD (voice)(1 ep)
as Chief Clerk Blu-Ray (voice)(1 ep)
as Usopp (voice)
as Teddie (voice)(25 eps)
as Ikuro Fukumoto (voice)(12 eps)
as Feitan (voice)(13 eps)
as Usopp (voice)
as Shinichi Kudo (voice)
as Usopp (voice)
as Usopp (voice)
as White Deer (voice)
as Fujino (voice)
as Heart (voice)
as Shinichi Kudo / Kaito Kid (voice)
as Kaito Kuroba / Kaito Kid (voice)(12 eps)
as Garizo (voice)(751 eps)
as Ain-I of the Neutral (voice)(1 ep)
as Usopp (voice)
as Daitokuji (voice)
as Mulmul (voice)
as Ryohei Nakanishi (voice)
as L (voice)
as Shinichi Kudo (voice)
as Shinichi Kudo (voice)
as Kijimuna(63 eps)
as Satoshi Ideguchi (voice)(25 eps)
as Usopp (voice)
as Ranma Saotome ♂ (voice)
as Inuyasha / Ranma Saotome ♂ (voice)
as Shinichi Kudo (voice)
as Rune(26 eps)
as Chamberlain
as Chimchar (voice)
as L (voice)
as Chic Jefferson (voice)(2 eps)
as Shin'ichi Kudo (voice)
as Male 'Awakened' 3 (voice)(2 eps)
as Usopp / Lashes (voice)
as Fûta (voice)
as L (voice)(37 eps)
as Flappy (voice)
as Hamura Shou (voice)(2 eps)
as Shinichi Kudo (voice) / Kaito Kuroba (voice)
as Hugh (voice)(51 eps)
as Usopp (voice)
as Flappy (voice)(49 eps)
as Kaikaimaru (voice)(11 eps)
as 乌索普
as Shinichi Kudou (voice)
as Raimon Tarou(145 eps)
as Hideyoshi Soya (voice)(21 eps)
as Usopp (voice)
as Inuyasha (voice)
as BB Runner
as Professor Daitokuji / Lyman Banner (voice)(180 eps)
as Hikorou Oikawa (voice)(12 eps)
as Kaito Kid / Shinichi Kudou (voice)
as Kenta Suetake(13 eps)
as Hachibee(26 eps)
as Tororo(51 eps)
as Usopp (voice)
as Thousanian Gineka (voice)(1 ep)
as Retro (voice)
as Inuyasha (voice)
as Usopp (voice)
as Shinpachi Nagakura (voice)(24 eps)
as Artemis (voice)(49 eps)
as Chappy / Dr. Gunma (voice)(26 eps)
as Saburo Kazeta/Inazuman
as Shinichi Kudo (voice)
as Usopp (voice)
as Sorata Muon (voice)(12 eps)
as Ogawa (voice)(3 eps)
as Ogawa(3 eps)
as Inuyasha (voice)
as Tochiro (voice)(13 eps)
as Haruhiko (voice)(25 eps)
as Goku (voice)(52 eps)
as Araiguma-kun
as Barubeat (voice)
as Usopp (voice)
as Shinichi Kudo (voice)
as Fujino (voice)(663 eps)
as Rokuta (voice)(45 eps)
as Tomonori Iwaki(24 eps)
as Nin-Nin
as Roualt (voice)
as Usopp (voice)
as Usopp (voice)
as Inuyasha (voice)
as Bashatt(26 eps)
as Shinichi Kudo (voice)
as Usopp (voice)
as Usopp (voice)
as Delibird (voice)
as Saburo Kazeda (voice)(17 eps)
as InuYasha (voice)(193 eps)
as Ryuichi Sakuma (voice)(13 eps)
as Rokuro Kanda (voice)(2 eps)
as Shesta (voice)
as Shinichi Kudo (voice)
as Usopp (voice)
as Poindexter
as Usopp (voice)(1180 eps)
as Ryuuichi Sakuma(2 eps)
as Parasect (voice)
as Shinichi Kudo / Kaito Kuroba (voice)
as Jorrne(26 eps)
as Keita Aono (voice)(26 eps)
as Noin Claude(44 eps)
as Kakeru
as Kakeru (voice)(4 eps)
as Kakeru(4 eps)
as Kyoichiro Narugami(39 eps)
as Low (voice)(26 eps)
as Etoh (voice)
as Sada
as Shinichi Kudo (voice)
as Taro Yoshida (voice)(26 eps)
as Crane Bahnsteik (voice)(26 eps)
as Rhint (voice)(1 ep)
as Yasuharu Musashino
as Manabu (voice)
as Kaito Kid
as (voice)(26 eps)
as Shinichi Kudo (voice)
as Shiori's boyfriend (voice)(39 eps)
as Sasuke (voice)
as Takuma (voice)(3 eps)
as Kappei Inagaki (voice)(2 eps)
as Hajime Kindaichi (Voice)
as Shibuya (voice)
as バース (voice)(3 eps)
as カナビー(75 eps)
as Astra / Announcer Banjou (voice)
as Scrib Lowengren
as Nin-Nin (voice)(4 eps)
as Takuya Enoki (voice)(35 eps)
as Camilla (voice)(25 eps)
as Tsutomu Yamaguchi (voice)
as Julian (voice)(2 eps)
as Hanabishi Satoshi(2 eps)
as Kenta (voice)(6 eps)
as Shinichi Kudo (voice)(1221 eps)
as Scrib Lowengren (voice)
as Tsutomu Yamaguchi (Voice)(50 eps)
as Takuro Amano(51 eps)
as Zenki (voice)(51 eps)
as Ushiwaka Nanbu (voice)(2 eps)
as Ryou Ishizaki (voice)(47 eps)
as Baki Hanma
as Ranma Saotome ♂ (voice)
as Daisaku Kusama (voice)
as Onimaro (voice)(10 eps)
as Dick (voice)
as Dick (voice)(2 eps)
as Shibuya (voice)
as Sai Saici (voice)(49 eps)
as (voice)(52 eps)
as Ken Kurenai(49 eps)
as Fake Ken(49 eps)
as Nicole (voice)
as Subaru Sumeragi
as Daisaku Kusama (voice)
as Kyota Suzuki (voice)
as Hirohiko Kazama (voice)(6 eps)
as Soldier Utsunomiya (voice)(1 ep)
as Etekichi(50 eps)
as Yūgo (voice)
as Yugo (voice)(2 eps)
as Kiwami Juurouta(52 eps)
as Bostov (voice)(2 eps)
as Yuuya Noda (voice)(51 eps)
as Kenichi Oono (voice)
as Virgil
as Subaru Sumeragi
as Subaru Sumeragi (voice)(2 eps)
as Hanahei Yamada (voice)
as Suke Banji (voice)
as Ranma Saotome ♂ (voice)
as Katsumi Shibuya (voice)
as Katsumi Shibuya (voice)(3 eps)
as Daisaku Kusama(7 eps)
as Daisaku Kusama
as Nin-Nin (voice)(14 eps)
as Wan Dababatta(7 eps)
as Toto (voice)(52 eps)
as Ougi (voice)
as Billia (voice)
as Oscar Cloud (voice)
as Tenma Koizumi (voice)(6 eps)
as Ranma Saotome ♂ (voice)
as Hikari Yumenokōji (voice)(51 eps)
as Arslan (voice)(6 eps)
as Young Munchausen II (voice)
as Amaru Ryudou(12 eps)
as Ryū-ō (voice)(2 eps)
as Akiba Shuu(5 eps)
as Ginjiro Yamazaki (voice)
as (voice)
as Madara (voice)(2 eps)
as Johnny (voice)
as Saburo Tenma
as Kenichi Oono (voice)
as Wakabayashi Osamu (voice)(6 eps)
as Sosuke Inukawa (voice)(13 eps)
as Hiroaki Kusano (voice)
as Etoh (voice)(13 eps)
as Hamahama (voice)(39 eps)
as Yūsuke Yamamoto(2 eps)
as Yattarou(54 eps)
as Kanata Tokino
as Tombo (voice)
as Ranma Saotome ♂ (voice)(161 eps)
as Eon(2 eps)