Ōshima JOUN was born into a family of sculptors and was famous for his skill in bronze casting. He was the son of Ōshima Takajiro, whose own father, Ōshima Yasubei, was the first sculptor in the family. He was a professor at the Tokyo School of Fine Arts (東京美術学校 Tōkyō Bijutsu Gakkō, name changed in 2008 to Tokyo University of the Arts) from 1887 to 1932.
His studio, Sanseisha—run by his brother Ōshima Yasutaro, also a talented artist—was very successful and at one point employed 11 assistants. During the period 1875–1879, the studio “produced some of the finest bronzes ever produced in Japan” [Encyclopædia Britannica, 11th ed., 1911. sv “Japan/Bronze Casting.” Cambridge: University Press.]. Many of Joun's students (Ryūki, Chōkichi Suzuki (see mention in the Victoria and Albert Museum), Sessei Okazaki, Kumazō Hasegawa, Gorosaburō Kanaya, Eisuke Jomi) achieved their own distinctions.
He exhibited at the 2nd National Industrial Exhibition in 1881, at the Paris World's Fair (1900) and at the Japan-British Exhibition of 1910.
Ōshima Joun died in Tokyo on January 4, 1940, at the age of 83.
Several of Joun's sculptures are exhibited at the Tokyo University of the Arts Art Museum, The National Craft Museum, the Museum of Imperial Collections, Guimet Museum (Paris), Tokyo National Museum, …