Hiroshi Masuoka was a Japanese actor and voice actor born on August 7, 1936, in Minami, Saitama Prefecture. He was affiliated with the Tokyo Actor's Consumer's Cooperative Society, also known as Haikyo, for much of his career. Masuoka passed away on March 21, 2020, at the age of 83.

His path to becoming a voice actor was indirect. Initially aspiring to be a painter, he studied at the Tokyo University of the Arts but left after two years to pursue his artistic vision more freely. He first became involved in theater through stage art, and his entry into acting happened by chance when he was asked to fill in for an actor who had left a production. He began voice acting around 1963, the dawn of television animation in Japan, and it gradually became his full-time profession. His debut role was as Okuma in the 1963 series "Werewolf Ken".

Throughout his extensive career, Masuoka became known for several iconic and long-running roles. He is most famously associated with two beloved characters: Masuo Fuguta in the long-running anime "Sazae-san," a role he played from 1979 until his retirement in 2019, and Jam Ojisan (Uncle Jam) in "Soreike! Anpanman," which he voiced from the show's premiere in 1988 until 2019. He also took over the role of Kame-Sennin, also known as Master Roshi, in the "Dragon Ball" series following the death of the previous voice actor, Kōhei Miyauchi, voicing the character in the later episodes of "Dragon Ball Z" and throughout "Dragon Ball GT".

In addition to these signature roles, Masuoka had a prolific career with a vast number of credits. This includes his role as Geronimo Junior, also known as 005, in the 1966 theatrical film "Cyborg 009" and subsequent works. He was a regular presence in the works of Go Nagai, appearing in series such as "Cutey Honey" as Naojiro Hayami and "Voltes V" as Defense General Oka and Do Zuul. He also voiced Toshio Asakura, the father of the main character Minami, in the "Touch" series of television anime and films. Other notable roles included Dr. Deko in "Cybot Robotchi", Zenmaijikake (Gizmo) in "Superbook" season 2, Master Luo in "Kung Fu Boy Chinmi", and Juukichi Ooyama in the anime "The Sound of Waves". His work extended beyond animation to tokusatsu (live-action special effects) series, where he frequently voiced villains and monsters in shows like "Android Kikaider" and provided narration for "Hyakujuu Sentai Gaoranger".

Beyond his performance work, Masuoka contributed to the industry as an educator, teaching at the Tokyo Animator Academy alongside fellow voice actors Masako Nozawa, Kaneta Kimotsuki, and Fuyumi Shiraishi. He also founded and ran a theater company called "Tokyo Renaissance". In recognition of his long-standing contributions to the voice acting profession, he was awarded the Achievement Award at the 12th Seiyu Awards in 2018.

Masuoka's career spanned over six decades, during which he brought warmth and character to hundreds of roles. His decision to retire from his two most famous roles in 2019 was his own, made out of consideration for the future of the long-running series. He passed away the following year, leaving behind a legacy as one of Japan's most cherished and hardworking voice actors.