Lee was born in Belgravia, England, the son of Contessa Estelle Marie (née Carandini di Sarzano) and Lieutenant-Colonel Geoffrey Trollope Lee of the 60th King's Royal Rifle Corps. Lee's mother was a famous Edwardian beauty who was painted by Sir John Lavery, as well as Oswald Birley and Olive Snell, and was sculpted by Clare F. Sheridan, a cousin of Sir Winston Churchill. Lee's maternal great-grandfather had been an Italian political refugee who sought refuge in Australia.

In 1946, Lee gained a seven-year contract with Rank Organisation after discussing his interest in acting with his mother's second cousin Nicolò Carandini, the Italian Ambassador. Carandini related to Lee that performance was in his blood as his great-grandmother Marie Carandini had been a successful opera singer in Australia, a fact of which Lee was unaware. He made his film debut in Terence Young's Gothic romance, Corridor of Mirrors, in 1948.

In 1948, Lee made an uncredited appearance in Laurence Olivier's film of Hamlet as a spear carrier (marking his first film with frequent costar Peter Cushing, who played Osric). Throughout the next decade, he made nearly thirty films, playing mostly stock action characters.

Lee's first film for Hammer, made in 1957 with his close friend Peter Cushing, was The Curse of Frankenstein in which he played Frankenstein's monster. That led to his first appearance as the infamous Transylvanian bloodsucker in the 1958 film Dracula (known as Horror of Dracula in the US).

Stories vary as to why Lee did not feature in the 1960 sequel The Brides of Dracula. Some state Hammer were unwilling to pay Lee his current fee but most tend to believe that he simply did not wish to be typecast. Lee did, however, return to the role in Hammer's Dracula: Prince of Darkness in 1965. Lee's performance is notable in that he has no lines, merely hissing his way through the film.

Again, stories vary as to the reason for this: Lee states he refused to speak the poor dialogue he was given, but writer Jimmy Sangster claims that the script did not contain any lines for the character. This film set the standard for most of the Dracula sequels in the sense that half the film's running time was spent on telling the story of Dracula's resurrection and the character's appearances were brief.

Lee has gone on record to state that he was virtually 'blackmailed' by Hammer into starring in the subsequent films; unable or unwilling to pay him his going rate, they would resort to reminding him of how many people he would put out of work if he did not take part.

His performances in the following three films (1968's Dracula Has Risen from the Grave, 1969's Taste the Blood of Dracula and 1970's Scars of Dracula) all gave the character very little to do but were each commercially successful. Although Lee may not have liked what Hammer were doing with the character, worldwide audiences embraced the films which are now considered classics of the genre.

Lee starred in two further Dracula films for Hammer in the early 70's, both of which attempted to bring the character into the modern day era. Neither was commercially successful. Lee's other work for Hammer included performances as The Mummy (1959), Rasputin in Rasputin, the Mad Monk (Lee apparently met Rasputin's assassin Felix Yussupov when he was a child), and Sir Henry Baskerville to Cushing's Sherlock Holmes in The Hound of the Baskervilles.

He was also responsible for bringing acclaimed occult author Denis Wheatley to Hammer. The company made two films from Wheatley's novels, both starring Lee. The first, 1967's The Devil Rides Out, is generally considered to be one of Hammer's crowning achievements. According to Lee, Wheatley was so pleased with it that he offered the actor the film rights to his remaining black magic novels free of charge.

However, the second, 1976's To the Devil a Daughter, was fraught with production difficulties, and was disowned by its author. Although financially successful, it was Hammer's last horror film, and marked the end of Lee's long association with the studio that brought him fame.

Lee also co-starred with Boris Karloff in the 1958 film Corridors of Blood. Like Cushing, he also appeared in horror films for other companies during the 20 year period from 1957 to 1977. Notable performances included the Jekyll and Hyde roles in I, Monster (1971), The Creeping Flesh (1972) and Lee's personal favourite The Wicker Man. Lee was attracted to the latter role by screenwriter Antony Schaffer and apparently gave his services for free as the budget was so small.

Since the mid 70s Lee has eschewed horror roles almost entirely, proving himself to be an extremely able and versatile actor. He played in the well-known James Bond series. Ian Fleming, author of the James Bond spy novels, had offered him the role of the title character in the first official Bond film Dr. No. Lee enthusiastically accepted, but the producers had already chosen Joseph Wiseman for the part. In 1974, Lee finally got to play a James Bond villain when he was cast as the deadly assassin Francisco Scaramanga in The Man with the Golden Gun.

Because of his filming schedule in Bangkok, film director Ken Russell was unable to sign Lee to play The Specialist in Tommy (1975). That role was eventually given to Jack Nicholson. According to an AMC documentary on Halloween, John Carpenter states that he offered the role of Sam Loomis to Peter Cushing and Christopher Lee before Donald Pleasance took the role.

Years later, Lee would meet Carpenter and tell him that the biggest regret of his career was not taking the role of Dr. Loomis. In 1978, Lee surprised many people with his deft comedy timing and willingness to go along with a joke as guest host on NBC's Saturday Night Live.

Lee also appeared in the series of Fu Manchu films from 1965 to 1969, starring as the eponymous villain in heavy oriental make-up. In 1998, Lee starred in the role of Muhammad Ali Jinnah, founder of modern Pakistan, in the film Jinnah.

He auditioned for a role in The Longest Day but was turned down as he did not look like a military man (despite having served in the RAF during World War II). Lee acted in the 1970 movie Eugenie unaware that it was softcore pornography, because the sex scenes were shot separately and edited in with his own appearances afterwards.

Lee has played roles in over 220 films since 1948. He has had many notable television roles, including that of Flay in the BBC television miniseries, based on Mervyn Peake's novels, Gormenghast, and Stefan Cardinal Wyszyński in the 2005 CBS film John Paul the Second. He played Lucas de Beaumanoir, the Grand Master of the Templar Order, in the 1990s BBC/A&E co-production of Sir Walter Scott's 'Ivanhoe.'

Lee starred as Saruman in the Lord of the Rings movie trilogy. (In the commentary he states he was approached to play Gandalf, but said he was too old. Gandalf was then given to Ian McKellen and Lee played Saruman.) Lee had met Tolkien once (making him the only person in the Lord of the Rings film trilogy to have done so), and makes a habit of reading the novels at least once a year.

In addition, he performed for the album The Lord of the Rings: Songs and Poems by J. R. R. Tolkien in 2003. Lee had his appearance in the third film cut, resulting in a frosty friendship with Peter Jackson, however, it was reinstated in the extended edition.