After years of work, Sugawara finally established himself as a famous actor at the age of 39, with the lead role of Shozo Hirono in the Battles Without Honor and Humanity series (1973–1976) of yakuza films.

[1] In 1980, Sugawara won the Japan Academy Prize for Best Supporting Actor for his role as a detective in the satirical Taiyō o Nusunda Otoko (1979).

As an adult he entered Waseda University's law program, but was dropped in his second year for failing to pay and began work as a model.

[5] However, when Shintoho filed for bankruptcy in 1961, Sugawara moved to the Shochiku studio where he was cast in Masahiro Shinoda's Shamisen and Motorcycle, but was fired from the role for coming to set late after a night drinking.

Also in 1975, he starred in the comedy Torakku Yarō: Go-Iken Muyō as love-seeking truck driver Momojiro Hoshi, which launched a successful ten-installment series.

[3] Sugawara won the 1980 Japan Academy Prize for Best Supporting Actor for his role as a detective in Kazuhiko Hasegawa's 1979 satirical film Taiyō o Nusunda Otoko.