Mark Oristano is an American voice actor based in Dallas, Texas, known for his work in English-language dubs of Japanese anime. Before entering the voice acting field, Oristano had a long career as a sportscaster, spending thirty years covering professional football including work on the Houston Oilers and Dallas Cowboys radio networks. He was a television sports anchor in Nashville, Tennessee, and later worked on Ron Chapman's morning show on KVIL-FM in Dallas for nearly twenty years. Oristano left broadcasting in 2002 to focus on creative work including portrait photography and stage acting, becoming a veteran stage actor in the Dallas theater scene. He has also worked as a writer and performer, creating the one-man show And Crown Thy Good: A True Story Of 9-11 and authoring books including A Sportscaster's Guide to Watching Football and Surgeon's Story.

In anime, Oristano is best recognized for his role as Riku Doldo III in the long-running series One Piece. Riku Doldo III is the former king of the kingdom of Dressrosa, also known as the King of Miracles, and appears in the anime beginning with episode 636. He has voiced a number of other characters across various anime series. In Fairy Tail, he voiced Hyberion. In Attack on Titan, he contributed additional voices. He played the role of Commander Ozaki in Space Battleship Yamato 2202:愛的戰士們 第二章 發進篇. In Sakura Quest, he voiced a character named Shiozaki. He provided additional voices for Black Clover, Magical Girl Spec-Ops Asuka, and Date A Live. In Blood Blockade Battlefront, also known as Kekkai Sensen, he voiced the character of Director. Oristano also played the role of Naguri in One Piece in addition to his work as Riku Doldo III, and voiced a character listed as Man with Briefcase in the crime drama Karma Police. His voice acting work frequently includes roles listed as Additional Voices, indicating a career focused on supporting and background character work in English dub productions.

Oristano has also performed live-action acting roles, appearing as Gennaro Angiuloa in the crime film Killer By Request and as Father Roberto in the comedy-drama Bail Out. While he has worked across multiple anime productions, no consistent pattern of collaborations with specific directors, studios, or fellow voice actors is clearly documented in available career sources. His career is notable for its transition from decades in sports broadcasting to a second act as a creative artist in theater, literature, and anime voice work.