Gray was born Donald Marshall Gray in Bournemouth, Dorset, the son of Maude Elizabeth (née Marshall) and Donald Gray, who was a surveyor. Gray attended Bournemouth School alongside Benny Hill, whose school had been evacuated to the same buildings, during the Second World War. Some of his friends remember that his bedroom walls were plastered with pictures of film stars. By his mid-twenties, Gray left his first job as a clerk for a real estate agent to become an actor. He began his stage experience at the theatre club next to Bournemouth’s Palace Court Hotel, where he was a last-minute cast replacement in The Beaux’ Stratagem. Gray surprised everyone, including himself, with the quality of his performance. When he moved away from Bournemouth in the late 1950s, his parents remained at the family home until their deaths. On becoming a professional actor he had to change his name, as there was already an actor named Donald Gray. He chose Charles Gray partly because Charles was the name of his maternal grandfather, partly because he had a close friend named Charles, and partly because he thought it sounded nice. For his first appearance on Broadway, in the 1961 musical Kean, he went under the name Oliver Gray. Charles Gray distinguished himself in theatrical roles, in the Regent’s Park Open Air Theatre, London, at the Royal Shakespeare Company, Stratford-Upon-Avon, and at the Old Vic. He received his vocal training at the RSC and became noted for his imposing stage presence; features which would translate impressively to character parts on screen.

During the 1960s, Gray established himself as a successful character actor and made many appearances on British television. Work in this period included Danger Man with Patrick MacGoohan and Maigret. Gray also appeared opposite Laurence Olivier in the film version of The Entertainer (1960) as a reporter. In 1964 he played murderer Jack Baker in the Perry Mason episode, “The Case of the Bullied Bowler”. His breakthrough year came in 1967 when he starred with Peter O’Toole and Omar Sharif in the WWII murder-mystery film The Night of the Generals. The following year he played Henderson, an Australian intelligence officer assigned to the Australian Embassy in Tokyo, in the 1967 Bond film You Only Live Twice. Four years later he appeared as Ernst Stavro Blofeld in the James Bond movie Diamonds Are Forever, both films starring Sean Connery as Bond. These make Gray one of the small number of actors to have played a villain and a Bond ally in the film series, another being Joe Don Baker (who played Brad Whitaker in The Living Daylights, and CIA agent Jack Wade in both GoldenEye and Tomorrow Never Dies). Gray’s most prolific work as an actor was between 1968 and 1979 when he appeared in more than forty major film and television productions. In this period he is perhaps best known for portraying the Criminologist (the narrator) in The Rocky Horror Picture Show, and a similar character, Judge Oliver Wright, in its 1981 sequel Shock Treatment. This more expansive role is said to be the same character, as the criminologist was not named in The Rocky Horror Picture Show, and would be congruent with the legal characteristics of Judge Wright. In 1983, he starred alongside Coral Browne and Alan Bates in the award-winning TV film An Englishman Abroad. In 1985, he starred in an episode of the BBC TV detective series Bergerac, entitled ‘What Dreams May Come?’ and involving black magic, disappearing mysteriously in the last scene. Other well-known film work includes The Devil Rides Out, Mosquito Squadron, Cromwell and The Beast Must Die.

Gray portrayed Mycroft Holmes in both the 1976 film The Seven-Per-Cent Solution and opposite Jeremy Brett’s Sherlock in four episodes of the 1984 Granada Television series The Adventures of Sherlock Holmes. In two episodes of the final Brett series, The Memoirs of Sherlock Holmes, he had leading roles as Mycroft, the first because Watson actor Edward Hardwicke was busy on another film project and the second as a result of Brett’s illness. Other television appearances include Dennis Potter’s Blackeyes, The New Statesman, Thriller, Upstairs, Downstairs, Bergerac, Porterhouse Blue plus a range of Shakespearean roles, such as Caesar in Julius Caesar and Pandarus in Troilus and Cressida. He regularly dubbed for Jack Hawkins after Hawkins’s larynx was removed to combat throat cancer, as the two otherwise highly distinctive men’s voices were similar. An example of this is in the film Theatre of Blood. Gray died of cancer on Tuesday, 7 March 2000. He was cremated at Golders Green Crematorium where his ashes remain.