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.
All Grown Up!
Law & Order
Kate & Allie
Shark
Desperate Housewives
Providence
Judging Amy
Heroes
Boy Meets World
The Batman
Walker, Texas Ranger
Evil Con Carne
JAG
Bonkers
The Wild Thornberrys
Law & Order: LA
The Angry Beavers
Rugrats
Max Steel
CSI: Miami
Law & Order
WTF 101
The West Wing
Tom & Jerry Kids Show
Rock, Paper, Scissors
Crossing Jordan
Super Dave: Daredevil for Hire
Gargoyles
Lefou (voice)
Guido
Man on Cross
Julio Mamani (voice)
Madero
Jesus
Boskov the Bear/Commando (voice)
Interviewer / Mr. Carter
Jose
Issac/David
Hector Molinas
Mr. Manchas (voice)
Kianga
Maitre D'
Coach Parra
Italian FBI Agent
Armand Kristopolous
Colonel
Spanish Dignitary (voice)
Cop (at Quality Café)
Newscaster (voice)
Gonzalo (voice)
Bitores Mendez (voice)
Herman's Trainer
Tony
Super
Sly (singing voice)
Lefou (voice