[2] The son of a Kamakura railroad magnate, Sugawara became a real estate developer and industrialist, notably effecting the subdivision, improvement, and accessibility of Kamakurayama (the city's mountain district) as a high-end residential area in the 1930s.

)[14] In the 1960s Sugawara chaired the Japanese National Committee for the Struggle Against Addiction to Drugs, estimating in 1965 that one-third of China's opium output was smuggled into Japan every year, pulling from its annual economy the 2021 equivalent of US$1.5 billion.

[17] Sugawara was an avid art collector, particularly of Japanese and Chinese antiquities, founding the Tokiwayama Bunko (Library) Foundation to hold and catalog his acquisitions, which the organization continues to display at special events and museum exhibitions.

[21] In 1966, Prime Minister Eisaku Satō appointed Sugawara as chairman of the Council for National Foundation Day, which recommended the establishment of an official government holiday every 11 February to commemorate the founding of Japan.

[22] A friend of Yasujirō Ozu, Sugawara appeared in seven of the director's last eight films, making him a ubiquitous presence in many of the most popular and accessible works of "one of the most influential and famous filmmakers in the history of Japanese cinema.

"[23] For example, in Good Morning, the Ozu film in which a viewer is most likely to infer that Sugawara is playing himself, he is asked at a bar to comment on journalist Sōichi Ōya's 1957 warning that television was part of a mass media campaign to turn Japan into "a nation of 100 million idiots.