[2] Andersson was notable for being the only Swedish rider to win an FIM road racing world championship.

In 1969 he finished second in the 250 championship after a season-long battle with Santiago Herrero and eventual champion Kel Carruthers.

[2] These impressive results earned him a place on the Yamaha factory 250 cc racing team as Rod Gould's teammate for the 1970 season, in which he finished third.

[6] Among other projects, Andersson had an important role in developing the three-cylinder 350 cc bike that Takazumi Katayama rode to win the 350cc road racing world championship in 1977.

[6][7] Andersson continued racing in his later years just for fun at an amateur level in Sweden, but did so well that he won the Supermono National Championship in 1995 at the age of 53.