Grant trained as an actor at the Royal Academy of Dramatic Art, working in his spare time as a frozen food salesman and also (coincidentally, in view of his later career) as a bus driver. After doing national service in the Royal Artillery, he made his stage debut in 1952 as Sydney in Worm's Eye View at the Court Royal, Horsham. In 1954 he married Jean Hyett; the marriage would end in divorce.