Katsumi Toriumi is a Japanese voice actor and actor affiliated with the talent agency Production Baobab. He was born on November 6, 1963, in Saitama Prefecture, Japan.

Toriumi began his career in entertainment as a child actor, joining a theater troupe at the age of seven. He made his voice acting debut in 1977 with a role in the anime series Raccoon Rascal. His first leading role came in 1983 when he voiced the protagonist Masato Wakamatsu in the television series Miyuki. He is a graduate of Nihon University Sakuragaoka High School.

Throughout his extensive career, Toriumi has portrayed a wide array of characters in anime, particularly during the 1980s and 1990s. He played Scott Heyward in the 1983 series Ginga Hyōryū Vifam. In 1985, he voiced Roanne Demitrich in Blue Comet SPT Layzner. He also took on roles such as a young Toki in Fist of the North Star and Bill Blythe in Metal Armor Dragonar. In the 1990 OVA White Fang, he voiced the character Russel Clagg. His film credits from this period include the role of a young Paul in the 1997 theatrical film The Dog of Flanders and the voice of a young Mao in the 2002 film Aterui.

In the 2000s, Toriumi continued to build his resume with prominent roles in major franchises. He is known for voicing Dalida Lolaha Chandra II in the Mobile Suit Gundam SEED series, a role he reprised in the 2024 film Mobile Suit Gundam SEED FREEDOM. He also voiced Elijah Kiel in the Mobile Suit Gundam SEED ASTRAY OVAs. Other notable roles include Hazuki in the Pokémon anime and Matsui in Kenichi: The Mightiest Disciple. He played Byakuya Matou in the first season of Fate/Zero and has had numerous guest roles in long-running series such as Case Closed (Detective Conan), Crayon Shin-chan, and Doraemon.

In addition to his work in anime, Toriumi has an extensive career in voice dubbing for foreign live-action films and television series. Some of his notable dubbing credits include providing the Japanese voice for Jesse in The Fast and the Furious (2005 TV Asahi edition), James "Caretaker" Farrell in The Longest Yard, and Chuck Gieg in White Squall. He also voiced characters in the television series Andromeda and dubbed the role of Michael in the 1988 VHS edition of E.T. the Extra-Terrestrial. His work in dubbing animation includes the voice of Roy in the film Wreck-It Ralph.