Koji Seto Biography: Wife, Child, Films, Awards, TV Series, Height, Parents, Age, Net Worth, Siblings

 
Koji Seto is a renowned Japanese actor and singer, celebrated for his versatile performances in television, film, and theater.

Known for his breakout roles as Wataru Kurenai in Kamen Rider Kiva (2008) and Hiro in Koizora (2008), he has established himself as a prominent figure in Japanese entertainment, associated with the D-Boys acting troupe under Watanabe Entertainment.

Profile

• Full Name: Koji Seto
• Stage Name: Koji Seto
• Born: May 18, 1988
• Age: 37 years old
• Birthplace: Kama, Fukuoka Prefecture, Japan
• Nationality: Japanese
• Occupation: Actor, Singer
• Height: 5 feet 8½ inches (1.74 m)
• Religion: Christianity
• Parents: Unknown
• Siblings: Saori Seto (younger sister)
• Spouse: Mizuki Yamamoto (m. 2020)
• Children: One
• Relationship: Married
• Net Worth: $2 million USD

Early Life and Education

Koji Seto, a talented actor and singer, was born on May 18, 1988, in Kama, Fukuoka Prefecture, Japan. Growing up as the eldest child with two younger sisters, including Saori Seto, he initially dreamed of becoming a veterinarian.

His passion shifted at age 15 after watching Satoshi Tsumabuki in the TV drama Orange Days, inspiring him to pursue acting.

With his parents’ support, he enrolled in a local acting school in Fukuoka, part of the Himawari Acting School. Details about his formal education are limited, but his training at the Fukuoka Actors School provided a strong foundation for his career. At 17, he moved to Tokyo to further his acting ambitions.

Career

Koji Seto debuted in 2005 as Makoto Kanno in the TV drama Rocket Boys. That same year, he won the Grand Prix 2nd Winner Award at Watanabe Entertainment’s 2nd D-Boys audition with his rendition of Masaharu Fukuyama’s “Himawari,” joining the D-Boys troupe.

His breakthrough came in 2008, when he simultaneously starred as Wataru Kurenai in Kamen Rider Kiva and Hiro in Koizora, a rare feat for a young actor.

As the lead vocalist of Tetra-Fang, he performed promotional songs for Kamen Rider Kiva. Notable roles include Satoru Okura in Atashinchi no Danshi (2009), Ariake Yamato in Otomen (2009), Eiji Kikumaru in Musical: The Prince of Tennis (2008–2009), and Mori Ranmaru in Gō: Hime-tachi no Sengoku (2011).

Other significant works include Shuhei in Rinne no Ame (2010), Yuta in Tumbling (2010), Takanori Ando in Sadako 3D (2012), and the spy in Spy Tokku (2012).

Recent projects include Kubi (2023) as Nobutaka Odani, Ichiban Sukina Hana (2023) as Yukue’s brother, and upcoming roles in Kakukaku Shikajika (2025) and Taigan no Kaji (2025).

Awards & Nominations

• 2005: Grand Prix 2nd Winner Award, Watanabe Entertainment’s 2nd D-Boys Audition  
• 2010: Ranked 7th Most Promising Actor, Oricon Poll

Social Media

• Instagram Handle: @koji_seto0518

Personal Life

Koji Seto, a celebrated actor, married actress Mizuki Yamamoto on August 7, 2020, after meeting on the set of Tokyo Alice (2017). They welcomed their first child in 2022. Residing in Japan, Seto maintains a private life, focusing on his family and career.

Known by the nickname “Setomaru,” he enjoys engaging with his 320,000 Instagram followers, sharing updates on his professional projects and occasional personal moments. His Christian faith, noted in some sources, influences his grounded persona.

Net Worth

Koji Seto, an accomplished actor and singer, has an estimated net worth of $2 million USD. His income is derived from acting roles, music projects with Tetra-Fang, and endorsements under Watanabe Entertainment.

Filmography (Selected):

• Rocket Boys (2005, TV) – Makoto Kanno
• Kamen Rider Kiva (2008, TV) – Wataru Kurenai (Lead Role)
• Kamen Rider Kiva: King of the Castle in the Demon World (2008) – Wataru Kurenai
• Koizora (2008, TV) – Hiro (Lead Role)
• Atashinchi no Danshi (2009, TV) – Satoru Okura
• Otomen (2009, TV) – Ariake Yamato
• Musical: The Prince of Tennis (2008–2009, Stage) – Eiji Kikumaru
• Rinne no Ame (2010, TV) – Shuhei (Lead Role)
• Tumbling (2010, TV) – Yuta (Lead Role)
• Gō: Hime-tachi no Sengoku (2011, TV) – Mori Ranmaru
• Sadako 3D (2012) – Takanori Ando
• Spy Tokku (2012, TV) – Lead Role
• Runway Beat (2011) – Supporting Role
• Judge (2013) – Supporting Role
• Kiyoku Yawaku (2013) – Kosei Nemoto
• Koi Suru Vampire (2015) – Supporting Role
• No Longer Heroine (2015) – Supporting Role
• Asura Girl: A Blood-C Tale (2017) – Supporting Role
• Tokyo Alice (2017, TV) – Supporting Role
• Confidence Man JP (2018, TV) – Supporting Role
• Lu over the Wall (2018) – Kai’s Father (Voice)
• Kubi (2023) – Nobutaka Odani
• Ichiban Sukina Hana (2023, TV) – Yukue’s Brother
• Kakukaku Shikajika (2025, TV) – Supporting Role
• Taigan no Kaji (2025, TV) – Supporting Role