Masahiro Inoue is primarily known as a Japanese live-action actor rather than an anime voice actor, with his career centered on tokusatsu productions and television dramas. Born in Kanagawa Prefecture on March 20, 1989, Inoue began his acting career in 2008 with a stage role as Keigo Atobe in the musical adaptation of The Prince of Tennis: The Imperial Presence, Hyotei Gakuen. He holds a first-degree black belt in Taekwondo and also practices Shorinji Kempo.

Inoue achieved widespread recognition in 2009 when he landed the lead role of Tsukasa Kadoya, the protagonist who transforms into Kamen Rider Decade, in the television series Kamen Rider Decade. This role remains his most iconic performance. As Kamen Rider Decade, he has reprised the character numerous times across the franchise, including in Kamen Rider Wizard, Kamen Rider Zi-O, Kamen Rider Gotchard vs. Kamen Rider Legend, and films such as Kamen Rider x Kamen Rider W & Decade: Movie War 2010, Kamen Rider x Super Sentai: Super Hero Taisen, and Kamen Rider Heisei Generations Forever. Beyond Kamen Rider, he has taken on other tokusatsu roles, including the antagonist Jinga in the Garo franchise, appearing in Garo: Goldstorm Sho and its sequel series Kami no Kiba: Jinga.

Regarding voice acting specifically for anime, no information is available. His voice performance work is largely confined to reprising his live-action tokusatsu roles in animated specials or film cameos. For example, he made his voice acting debut in the 2009 television special Kamen Rider G, providing the voice for Kamen Rider Decade, and he also voiced the same character in Kamen Rider Heisei Generations Forever. These are not traditional anime voice acting roles. Outside of his acting career, he was appointed as the representative director of AIC RIGHTS in January 2023. No recurring anime voice acting collaborations or traditional anime voice roles have been documented.