Kappei Yamaguchi

Mitsuo Yamaguchi, known professionally as Kappei Yamaguchi, is a Japanese voice actor and rakugoka born on May 23, 1965. He stands out in the industry for his ability to switch between high-energy comedic roles and subtle dramatic performances. His career spans over three decades, during which he has become one of the most recognizable voices in anime history.

Yamaguchi currently voices iconic characters like Usopp in One Piece, Inuyasha in Inuyasha, and L in Death Note. He also lends his voice to Shinichi Kudo and Kaito Kid in the long-running series Case Closed. Beyond animation, he performs in live-action projects and traditional storytelling arts. [edit]

Born Mitsuo Yamaguchi in Fukuoka Prefecture, he grew up with a strong interest in performance arts. Before entering the professional world, he enrolled at Tokyo Zokei University's Department of Art Design but left before graduating to pursue acting full-time. His early training included joining the theater group Gekidan Hidoribata, where he performed in radio dramas and stage plays. This period was crucial for developing his vocal control and timing.

He adopted the stage name Kappei Yamaguchi to distinguish himself from the more famous actor Mitsuo Yamaguchi. His official debut as a voice actor came in 1989 when he took on the dual role of Ranma Saotome in the anime Ranma ½. The character required him to switch between male and female voices seamlessly, showcasing a versatility that would define his future career. Prior to this breakthrough, he had already honed his skills as a rakugoka, a traditional form of Japanese comic storytelling, which added depth to his comedic timing. [edit]

His 1989 debut as Ranma Saotome launched him into stardom, establishing him as a master of energetic and comedic characters. Throughout the 1990s, he voiced Kaito Kid in Detective Conan and appeared in various anime films. A major turning point occurred in 2000 when he landed the lead role of Inuyasha in the long-running series Inuyasha, cementing his status as a top-tier seiyū. He reprised this role in the sequel Yashahime in 2020.

In 2004, he joined the cast of One Piece as Usopp, a role he has maintained for over two decades. His portrayal of the enigmatic detective L in the global phenomenon Death Note in 2006 further expanded his international reach. He continued to expand his repertoire by voicing Teddie in the critically acclaimed video game Persona 4 in 2008. Recent years have seen him continue his high-profile activity, including casting in the Gintama anime film Yoshiwara in Flames in January 2026 and joining the cast of the new anime Go for It, Nakamura! in April 2026. [edit]

Yamaguchi is portrayed in the media as a humble, hardworking, and versatile artist. He is known for his approachability and dedication to his craft. His social media voice is friendly and engaging, often sharing anecdotes from recording sessions. He is respected for pioneering the hot-blooded archetype in shonen anime while successfully transitioning to complex, quiet roles. [edit]

iFANN has not yet collected fame data for this person. The fanbase has no formal name. Fans are generally referred to collectively as "seiyū fans" or by the specific fandom names of the shows they love, such as "Straw Hat Pirates" for One Piece or "Detective Conan" fans. The fandom is highly organized, particularly around One Piece and Case Closed, where his characters are central. Fan campaigns often focus on ensuring the continuation of his roles and celebrating anniversaries of his debut. He interacts with fans through events like Seiyu Auditions and fan meetings, often signing autographs and participating in Q&A sessions. [edit]

Yamaguchi changed his name from Mitsuo to Kappei because there was already a famous actor named Mitsuo Yamaguchi. He is a trained rakugoka, a skill he integrates into his voice acting, particularly for comedic timing. Both of his children, Ryūnosuke and Akane, are successful voice actors, continuing the family trade. His portrayal of Ranma Saotome created a cultural moment where his voice became synonymous with the character. Being the voice of Usopp since 2004 makes him one of the longest-serving voice actors for a main character in a continuous anime series. [edit]

Kappei Yamaguchi is married to a non-celebrity partner; their marriage details have been kept private to protect her identity. They have two children who have followed in their father's footsteps: Ryūnosuke Yamaguchi, born in 1996, and Akane Yamaguchi, born in March 1996. Both children are active in the industry, with Akane specifically noted for her work in rakugo and voice acting. The family resides in Japan, maintaining a relatively low public profile compared to the father's fame. [edit]

Junko Takeuchi, Akiko Yajima, Ryūnosuke Yamaguchi, Akane Yamaguchi. [edit]

Public records regarding Kappei Yamaguchi's romantic life are sparse due to his preference for privacy. There are no documented dates, engagements, or divorces prior to his current marriage. He is married to an unnamed woman, a non-public figure. The couple met through professional circles or personal connections, though the specific circumstances remain unpublicized. They have raised two children together. As of 2026, Kappei Yamaguchi is married and has no reported separations or affairs. The relationship remains stable and private. No other public romantic relationships or flings have been confirmed by credible sources. [edit]

iFANN Editorial Team research estimates Kappei Yamaguchi's net worth at approximately $3 million USD as of 2026. His wealth stems from decades of voice acting royalties, particularly from long-running series like One Piece, Inuyasha, and Case Closed. Additional income sources include live concert performances, book sales on voice acting and rakugo, and endorsement deals. Real estate holdings in Tokyo and Fukuoka likely contribute significantly to his assets. Unlike some peers, he does not appear to have major business ventures outside of his production activities. [edit]

Yamaguchi has won multiple Seiyu Awards, including recognition for Best Lead Actor and Best Supporting Actor for roles such as Inuyasha and Ranma Saotome. He has received nominations for the Japan Academy Prize for voice acting excellence. [edit]