Shinji Mizushima was a fishmonger before he started illustrating in 1959. He started out at the Kashibon Manga Kage agency, where he drew several comics, like 'Ore wa Yaru' (1959), 'Thrill o Ajiwan Otoko' (1960), 'Muteki Dump Guy' (1961), 'Idaten Santa' (1962) and 'Heno Heno Mohji' (1964). He also illustrated 'Botchan', a comic adaptation of a classic novel in Japanese literature. He continued his career with working for several daily's and magazines, starting series like 'Takaou', 'Ushitsuki' and 'Left wa Shinazu'. From the late 1960s Mizshima specialized in sports comics, and specially baseball. Some of the titles in this genre include 'Otoko Doahou Koushien' and 'Abu-San'. In 1972 he started the 'Dokaben' series, which is published in Shônen Champion and later in 48 pocket books.
Shinji Mizushima died in 2022 at age 82.