Callum, born in 1912, was a son of Murdo and Mary Ann Maclean from 10 Breaclete. After leaving the Nicolson Institute he studied history at Edinburgh University. In 1934 he married Williamina "Winnie" Ross from Scarp and moved to London where he made a living marketing lobsters for the Bernera fishermen. After war broke out he joined the RAF (squadron leader) and was based in Iceland then Gibraltar. After the war ended he opened a stationers in Marchmont, Edinburgh and operated a printing press which, although self-taught, he soon mastered and by 1957 he founded Macdonald Printers and Publishers.

In 1972 he was presented with a Scottish Arts Council award in recognition of his services to literature and in 1982 was appointed honorary member of the Scottish Library Association in recognition of distinguished service to librarianship and the library profession. In the same year he retired from what had become Macdonald Printers. Williamina, with whom he had six children, died in 1986 and in 1989 he married poet Tessa Ransford. The National Library of Scotland mounted an exhibition of his publishing in 1987 and he was awarded an MBE in 1992.