He grew up in Johannesburg, and was in his teens when he served with the entertainment unit of the South African Army during World War II. After moving to London, England, he enrolled in the Royal Academy of Dramatic Art where he became known as Larry. After learning his craft at RADA, he began to perform on stage and film, where he adopted the stage name "Laurence Harvey", taken either from the shop name Harvey Nichols or from Harvey's Bristol Cream.
He made his cinema debut in the British film House of Darkness (1948) but didn't really establish himself in British cinema until 1954, when he appeared with Rex Harrison and George Sanders in King Richard and the Crusaders (1954) and as Romeo in Renato Castellani's adaptation of William Shakespeare's Romeo and Juliet, narrated by John Gielgud. This enabled him to break out of the "ghetto" of British films and get his first experience of Hollywood. He was cast as the writer Christopher Isherwood in I Am A Camera (1955), opposite Julie Harris as Sally Bowles. (The same book by Isherwood was later adapted into the musical play Cabaret, whose film version starred Liza Minnelli and Michael York.) He also appeared on American TV and on Broadway, making his Broadway debut in 1955 in the play Island of Goats, a flop which closed after one week, though his performance won Harvey a 1956 Theatre World Award. Harvey appeared twice more on Broadway, in 1957 with Julie Harris, Pamela Brown, and Colleen Dewhurst in William Wycherley's The Country Wife, and as Shakespeare's Henry V in 1959, as part of the Old Vic company, which featured a young Judi Dench as Katherine, the Daughter of King of France. In John Miller's biography of Dame Judi, With A Crack In Her Voice, she talked of being bewildered at how Harvey never actually looked at her during his speeches, and the book also quotes Joss Ackland as saying that Americans seemed to think Harvey was some sort of great actor, which his fellow actors certainly didn't.
Harvey was regularly dismissed by critics and disliked by fellow workers in the British theatre. In his posthumously published autobiography Knight Errant, Robert Stephens described him as "an appalling man and, even more unforgivably, an appalling actor."
Harvey was now a star. He was cast in the role that had made Peter O'Toole famous in the West End in the movie version of The Long and the Short and the Tall (1961) as O'Toole had yet to establish himself as a cinema star and Harvey was more "bankable". During the late 1950s and 1960s, Harvey appeared in several major films, including Butterfield 8 (1960), John Wayne's epic The Alamo (1960), Walk on the Wild Side (1962) with Barbara Stanwyck, Jane Fonda and Capucine, the film adaptation of Tennessee Williams's Summer and Smoke (1961) with Geraldine Page, and Darling (1965) with Julie Christie. In this period, he also appeared as Raymond Shaw in The Manchurian Candidate (1962), the role for which he is best known.
Harvey played King Arthur in the London staging of the Alan Jay Lerner and Frederick Loewe musical Camelot, in 1964 at Drury Lane. He became very good friends with Elizabeth Taylor and his Manchurian Candidate co-star Frank Sinatra, and was a member in good standing of high society, then dubbed "The Jet Set". Like Joe Lampton, he had made it to the top.
In the period of 1959-65, Harvey had the distinction of appearing opposite three actresses who won the Academy Award for their performances: Simone Signoret in Room at the Top, Elizabeth Taylor in Butterfield 8, and Julie Christie in Darling. In all three roles, he established his star persona of being a first-class heel. (Geraldine Page, his co-star in Summer and Smoke, was also nominated for a Best Actress Oscar but did not win.)
Bereft of a choice of better roles, Harvey returned to Britain to make the comedy The Spy with a Cold Nose (1966). His last hurrah was his appearance in the spy thriller A Dandy in Aspic (1968), which he took over after the original director Anthony Mann died during shooting. In 1968, in settlement of a dispute with Woodfall Films over the rights to The Charge of the Light Brigade (1968), Woodfall cast him in their version as a Russian prince. He performed as cast, but was never seen as the Prince in the finished film. The only part of his performance remaining in the final cut is a brief appearance of him in the background of one shot, as an anonymous member of a theatre audience.
Thereafter Harvey played out his career largely in undistinguished foreign films, TV work and the occasional supporting role in a major production. In The Magic Christian, he recited Hamlet's soliloquy, almost nude and very thin. A promising project, Orson Welles' The Deep (1970) with Jeanne Moreau, was never finished. One performance from this period was in a 1971 USA horror film television episode, titled "The Caterpillar", of Rod Serling's Night Gallery. He was also guest murderer of the week on Columbo in 1973, as a chess champion who murders his opponent.
Numerous accounts contend that Laurence Harvey was bisexual. In his account of being Frank Sinatra's valet, Mr. S: My Life with Frank Sinatra (2003), George Jacobs writes that Harvey often made passes at him while visiting Sinatra. According to Jacobs, Sinatra was aware of Harvey's sexuality but did not mind, joking that he had the handicaps of being gay, a Jew, and a "Polak" (sic), so people should go easy on him.
In his autobiography Close Up (2004), British actor John Fraser wrote that Harvey was gay and that his long-term lover was his manager James Woolf, who "discovered" Harvey in the 1950s. According to Fraser, "As a teenager, [Harvey] started out living with Hermione Baddeley, a blowsy star of intimate revue more than twice his age. Then he married Margaret Leighton, old enough to be his mother, but a woman of style. When this marriage was over, he married Joan Cohn, widow of Harry Cohn, managing director of Columbia Pictures. Throughout all these career marriages, he still managed to string Jimmy Woolf along."