[3] After leaving high school, Kobayashi worked for Japanese National Railways at Inagi-Naganuma Station until being spotted at a bodybuilding event and recruited as a professional wrestler in 1966 at the age of 25.

[5][11][12] Over the following two-and-a-half years, Kobayashi defended the IWA World Heavyweight Championship against a series of various challengers including Blackjack Lanza, Red Bastien, Baron von Raschke, Dusty Rhodes, Crusher Lisowski, Curtis Iaukea, Billy Robinson, Édouard Carpentier, Ivan Koloff, Dick Murdoch, Mad Dog Vachon, and Rusher Kimura.

[11][13][14] In July 1972, Kobayashi and Great Kusatsu won the vacant IWA World Tag Team Championship; they held the titles until April 1973 when they lost to Koloff and Vachon.

[18] The match was significant as hitherto top Japanese professional wrestlers traditionally only faced foreign opponents, not one another,[19] leading it to be described as a "forbidden battle".

On July 24, Kobayashi lost to NWA North American Heavyweight Champion Bob Armstrong in a "title versus hair" match.

Kobayashi left Florida later that month after he and Bobby Duncum lost a tag team loser leaves town match to Don Muraco and Jerry Brisco.

[15] He wrestled for NJPW throughout 1975, competing primarily against foreign opponents such as The Canadian Wildman, Steve Veidor, Killer Karl Krupp, Man Mountain Mike, The Hollywood Blonds, Hans Schmidt, Brute Bernard, Gilles Poisson, Greg Valentine, and Tiger Jeet Singh.

In February 1976, Kobayashi and Seiji Sakaguchi defeated Singh and Voodoo Malumba in the finals of a tournament for the vacant NWA North American Tag Team Championship.

[25] In August 1981, Kobayashi returned to NJPW, facing opponents such as Abdullah the Butcher, Bad News Allen, Billy Crusher, Hulk Hogan, and Stan Hansen.

[1] He wrestled his last ever match at New Japan Pro-Wrestling's twentieth anniversary show on 1 March 1992, teaming with Sakaguchi to defeat Singh and Ueda.

[28] After largely stepping back from wrestling in 1981, Kobayashi worked as a television and film actor under the stage name "Strong Kongô" until retiring in 1995.

[29] In later life, Kobayashi lived in a specialist nursing home in Ōme after becoming bedridden due to a spinal cord injury that paralyzed his lower body.