Tomohiro Nishimura is a Japanese actor, voice actor, singer-songwriter, theatre director, and sound director born on February 2, 1961, in Asahikawa, Hokkaido. He began his entertainment career in the early 1980s after moving to Tokyo with the aspiration of becoming a musician, performing live in the Kanto region. His professional name is written with the characters 西村 朋紘, though his real name and former stage name is written as 西村 智博, both read as Tomohiro Nishimura. He is also known by the nickname Omo, which originated from a childhood mispronunciation of his own name.

Nishimura made his debut as a voice actor in 1981 with the anime series Urusei Yatsura, where he was initially cast as the character Chibi but was later replaced due to his inexperience. He continued in the same series with the role of Kotatsu Neko, a character that required non-verbal acting, which he found to be a challenging but formative experience. He considers veteran voice actor Shigeru Chiba, whom he met while working on Urusei Yatsura, to be his mentor.

Throughout his career, Nishimura has built an extensive filmography, taking on a wide variety of roles across television animation, original video animations, animated films, and video games. He has provided voices for characters in numerous notable series, including Corkus in Berserk, Midvalley the Hornfreak in Trigun, Yoshito Yoshimoto in Magic User's Club!, and Chiharu Shiba in the Baki the Grappler series. He has also had recurring roles in long-running franchises, such as various characters in Detective Conan, Matt in Death Note, and SL-man in the Soreike! Anpanman films and television series.

His work in original video animations is particularly extensive. He is well-known for his portrayal of Amano Jaku across multiple installments of the Urotsukidōji series, including Legend of the Overfiend, New Saga, and Inferno Road. He also frequently voiced the character Shu Rei Fuan in various entries of the Yoroiden Samurai Troopers (Ronin Warriors) franchise, including the television series, Gaiden, and Message. Other prominent OVA roles include Edward T. Maclegan in Condition Green, Yan Noiman (Yang Neumann) in Macross Plus, and Tochirō in Cosmo Warrior Zero.

In addition to anime, Nishimura has contributed to tokusatsu productions, providing voices for characters such as Neko Signal in the film for Chouriki Sentai Ohranger and ZZ Zeli in Gekisou Sentai Carranger. His video game work includes Joachim Valentine in the Shadow Hearts series, Pesci and Ghiaccio in GioGio's Bizarre Adventure, and Klondike in Daemon X Machina. He has also been active in dubbing foreign content, voicing Butch in Tom and Jerry: The Magic Ring and Freddie in Thomas & Friends.

Beyond performance, Nishimura has taken on roles in production and direction. He was previously affiliated with the talent management firms Troubadour Music Office and 81 Produce but is now freelance. In 2003, he founded his own company, OMO Ltd., and has since been active as a sound director for video games, OVAs, and drama CDs. His work as a sound director demonstrates his broad expertise within the anime and entertainment industry. He has also maintained his musical pursuits as a singer-songwriter, releasing original albums under his former name, Tomohiro Nishimura (西村智博).