Career
While attending Seijo High School, he made appearances in numerous socialist films such as Ashizuri Misaki. After graduation he entered Eguchi Dance Institute and studied modern dance and the fundamentals of acting.
In 1961, he became the first actor to portray the Taisō no Onīsan in the Uta no Ehon program on Okaasan to Issho.
In February 1964, Sagawa married Nobuyo Ōyama after working with her on-stage in the play Son Goku. At the time they got married, she was a voice actor in the puppet show Boo-Foo-Woo on Okaasan to Issho, but since it was a different program from Sagawa's Uta no Ehon, they hardly ever got to meet behind the scenes.
Despite being married, they never had any children, as they lost their first child, a son, to stillbirth and their second child, a daughter named Erika, to lung and heart disease after only 3 months.
As a successor to Yukio Aoshima and Kokontei Shinba VIII in Ohiru no Wide Show, Sagawa served as a presenter in various fields. He appeared on the stage of Fuji Theater in 1985 and since then was active as an actor as well as in lecture activities.
In 1988, co-authored with Ōyama, the cookbook Keisuke-Nobuyo no Omoshiro Sōzai 170 was published by Shufunotomosha and became a best-seller, selling more than a million copies, and in 1991 they co-authored and released a follow-up entitled Keisuke-Nobuyo no Omoshiro Shukō.
In 2001, he published Kamisan ha Doraemon, a book about Ōyama's daily life as she suffered from cancer that year and the caregiving she received during that time.
In May 2009, he appeared in NHK Educational TV's 50th anniversary commemorative special program ETV50: Kodomo no Hi Special -Do Mitai Kyōiku TV Dai 2-dan- (Namahōsō) Okaasan to Issho as the first generation Taisō no Onīsan for the first time in about 40 years in costume and showed exercise gymnastics with the song "Genki ni Ichi, Ni".
Final years
In 2013, Sagawa announced that he had undergone surgery for early stage stomach cancer, but did not undergo chemotherapy.
On May 13, 2015, Sagawa publicly announced that his wife Ōyama was suffering from dementia and that he would be taking care of her, but a year later, while caring for Ōyama, Sagawa was diagnosed with kidney cancer so moved her to live at a facility to receive treatment for his illness.
In May 2017, Sagawa was hospitalized, and was readmitted the next month after suffering a cerebral infarction.
Death
Sagawa died from ureteral cancer on July 11, 2017, at the age of 80.
Ōyama visited him several times while he was in the hospital, but was unable to make it in time for his final moments before death. Although she served as the chief mourner, she did not attend his wake or funeral due to her dementia.
Following his hospitalization, Sagawa entrusted his affairs to he and his wife's manager Akiko Kobayashi. Ōyama continued to live at the facility while the management of their now-ownerless home was being handled by a tax accountant from Tokyo.
Years later following Sagawa's death, his wife Ōyama died of senility on September 29, 2024, at the age of 90.
