Stearn was a member of the Linnean Society[lower-alpha 8] for many years, becoming a fellow as early as 1934. He served as botanical curator 1959–1985, council member 1959–1963 and as vice-president 1961–1962 and president 1979–1982,[15][60] producing a revised and updated history of the society in 1988.[61] He also served as president of the Garden History Society and the Ray Society (1975–1977).