Yuji Mikimoto is the stage name of Masaru Miyashita, a Japanese actor and voice actor born on March 15, 1948, in Niigata Prefecture, Japan. He began his career in the 1970s, initially working in theater after training at the Toei acting academy and with groups such as Gekidan Kyo, before establishing himself in anime and foreign film dubbing. Throughout his career, he has been affiliated with several talent management agencies and is currently represented by Arts Vision.

Mikimoto's career in anime spans several decades, with a significant body of work from the 1980s onward. During this period, he became a recognizable presence in the mecha and action genres. In the Transformers franchise, he voiced the Autobot Pretender Diver in the 1988 Japanese-exclusive series Transformers: Super-God Masterforce. His involvement with the franchise extended to other entries, including Transformers: The Headmasters and Transformers: Victory. In the Gundam universe, he is known for the role of Chap Adel, a veteran mobile suit pilot and member of the Immortal 4th Team, in the influential OVA series Mobile Suit Gundam 0083: Stardust Memory. Another notable mecha role was in the 2004 television series Tetsujin 28-go, where he voiced Kenji Murasame, a character whose quest for revenge evolves into a complex alliance with the protagonist. This character is a recurring figure in works based on Mitsuteru Yokoyama's creations; Mikimoto also voiced an immortal version of Inspector Kenji Murasame in the acclaimed OVA series Giant Robo: The Animation. His work in the 1980s and 1990s also includes the role of Ramenman in the Kinnikuman: Kinnikusei Ōi Sōdatsu-hen series and Yarsand in Machine Robo: Battle Hackers.

Mikimoto's voice acting portfolio is extensive, encompassing numerous other prominent anime series. His credits from the 1980s include roles in Fist of the North Star, Saint Seiya (as Bear Geki and Centaurus Babel), and City Hunter. In the 1990s, he appeared in Slam Dunk, Mobile Suit Gundam Wing, Rurouni Kenshin, Trigun, and Cowboy Bebop. His work continued into the 2000s with roles in series such as Hellsing, Ghost in the Shell: Stand Alone Complex, Kino's Journey, and Code Geass: Lelouch of the Rebellion R2.

In addition to his anime roles, Mikimoto has had a prolific career in voice-over dubbing for live-action and animated foreign films. He has provided the Japanese voice for characters in a wide array of Hollywood films, including the TV Asahi edition of Back to the Future, Platoon, Executive Decision, and Judge Dredd. He is also known for being the regular Japanese voice for actor Harry Goaz, who played Deputy Andy Brennan in the television series Twin Peaks and its 2017 revival.

Throughout his long career, Yuji Mikimoto has built a reputation for his deep voice and his ability to portray both intense heroes and formidable villains. He is noted for a recurring collaboration with director Yasuhiro Imagawa, having been cast in several of the director's projects, including Giant Robo and Tetsujin 28-go. His professional standing is defined by his longevity, versatility, and the breadth of his contributions to the Japanese voice acting industry across animation and dubbing.