His debut manga was Sannen Kimen-gumi, published in Weekly Shōnen Jump beginning in 1980.
Highschool was a smash hit, and an animated version was begun in 1985, running for two years on Fuji TV, along with a movie in 1986 and two video games.
His next manga series was I'm Shitataka (僕はしたたか君, Boku wa Shitataka-kun), which ran from 1988 through 1990.
After Shitataka, Shinzawa took a break from publishing manga until 2001, when his current series, Flash!
Kimengumi has been called "the funniest manga I have ever read" by Michael Gombos, director of Asian marketing for Dark Horse.