His film career began in 1942, when producers from Ealing Studios were looking for a young Scot to act in "The Foreman Went to France" and he was suggested for the part. After this, he returned to his job at Rolls-Royce, but he was soon asked to do more films, and he made the decision to make acting his career. Jackson soon appeared in other films, including "Millions Like Us", "San Demetrio London", "The Captive Heart", "Eureka Stockade" and "Whisky Galore!". In the early years of his career, Jackson also worked in repertory theatre in Glasgow, Worthing and Perth.