He became an actor at Nikkatsu and made his film debut with "Ueru Tamashii" directed by Yuzo Kawashima in 1956.

[2] He solidified his popularity with such films as Nangoku Tosa o Ato ni Shite (A Farewell to Southern Tosa) and starred in the Wataridori series and "Senpūji" ("Whirlwind Child") film series.

Kobayashi, along with Yujiro Ishihara and others, formed the core of Nikkatsu Action's golden age.

[3] Kobayashi produced and starred detective tv drama series Target Men in 1971.

[6] Kobayashi was married to popular singer Misora Hibari in 1962, but the marriage ended in divorce two years later in 1964.