"McLean was on the teaching staff at Glasgow School of Art (GSA) in the mid 1930’s where he gained experience of film making with Norman McLaren, Stewart McAllister and other members of the GSA Kinecraft Society. He was called up to serve in the armed forces during the Second World War and after a brief return to teaching, entered the film industry with Scottish National Film Studios (SNFS) whose first premises in 1946 were in India Street, Glasgow. ... ‘Mac’ as he was known, soon found work with the Citizen’s Theatre in Glasgow and it was here that he became aware of Campbell Harper Films in Edinburgh. He successfully applied for a job with Alan Harper, recruited to work specifically on the production of the Glasgow Civics Series films for the Glasgow Education Committee. During his time at Campbell Harper Films Mac edited, directed and wrote sponsored, industrial and educational films. He was the only person employed in the late 1940’s as a film director in Scotland. Willie McLean also had a keen interest in sound recording equipment, and experimented in building his own sound system out of unused, collected parts. In 1960 he left Campbell Harper Films to join the film unit in the engineering film Ferranti."
Biography of 'MacLEAN, William J. ‘Mac’' via the National Library of Scotland Moving Image Archive.