Koichi Sato (佐藤 浩市, Satō Kōichi, born December 10, 1960) is a Japanese actor.

[6] Sato’s given name Koichi (浩市) was taken from one Kanji character each from the film directors name Hiroshi Inagaki (稲垣 浩) and Kon Ichikawa (市川 崑), with whom Mikuni was close at the time.

[6][Note 2] Sato said that he didn't really recognized Mikuni as a father[8] and that it was rather distressing to have dinner with him when he occasionally came home.

When he saw this film in the movie theater and saw his own image on the screen, he made a renewed decision to live his life as an actor.

"[20] In Sakamoto's Tokarev, Sato played the role of an infant kidnapper, and he discussed the character of this villain with the director, expressing his opinions.

[25] Debates about acting can get heated, and Sato and Sakamoto once got into a fight in a bar and were interceded by Yoshio Harada, who was there.

[28] Sato took on the challenge of a full-fledged comedy in The Magic Hour, a 2008 film directed by Mitani, in which he had never acted before.

[28] Since his debut, Sato used to insist what he thought as an actor and argued vehemently with the director on the set, as did his father.

Sato said that Mikuni probably did not think well of his attitude and behavior at the time, as if he was living by himself, and that in later years he gradually came to feel the weight of those words within himself.

[38][42] However, since the content of the movie was also about a father-son feud, Sato did not dare to deny the "non-getting along" theory at the time.

[43] However, after Sato's son Kanichiro was born in 1996, Mikuni dearly loved on his grandson and showed up at his sports event at school, and the father-son rift is said to have disappeared gradually.

[48] Close actor friends Akira Terao, Ryudo Uzaki, Noritake Kinashi, Yōsuke Eguchi, and Yukiyoshi Ozawa also participated in the live performances as guests.

He remarried in 1993 to stage actress Ayako Hirota, and their first son, Kanichiro, made his acting debut in 2017.

[16] Accepting the wishes of his wife, who is a volunteer, he has been working with the Tokyo Metropolitan Government's "Friend Home" program since around 2018 to temporarily care for children from infant homes and orphanages on weekends and during vacations through the foster care system.