The role of Winston Smith was taken by Peter Cushing, one of his first major roles. Cartier cast him after having been impressed with his performance in a BBC production of Anastasia the previous year. Cushing went on to become a film star, as would his co-star Donald Pleasence, who played Syme. Pleasence was the only member of the cast present in the 1956 feature film adaptation of the story, playing an amalgamation of Syme and Parsons with the latter's name.
Other cast members included Yvonne Mitchell, who had starred in the Kneale/Cartier Wuthering Heights, as Julia, and André Morell as O'Brien. Wilfrid Brambell, later known for his roles in Steptoe and Son and as Paul McCartney's grandfather in A Hard Day's Night, appeared in two roles, as the old man Winston speaks with in the pub and as a prisoner later on when Winston is incarcerated. Nigel Kneale, who had briefly acted in the 1940s before turning to scriptwriting, had a small voice-over role as an announcer. The face of Big Brother was Roy Oxley, a member of the BBC design department whose inclusion was something of an in-joke on the part of the production team.