David Hemmings was born in Guildford, in the county of Surrey, to a biscuit salesman father. His education at Alleyn's School, Glyn Grammar School in Ewell and the Arts Educational School, led him to start his career performing as a boy soprano in several works by the composer Benjamin Britten, who formed a close friendship with him at this time. Most notably, Hemmings created the role of Miles in Britten's chamber opera Turn of the Screw (1954). His intimate, yet innocent, relationship with Britten is described in John Bridcut's book Britten's Children (2006). Although many commentators identified Britten's relationship with Hemmings as based on an infatuation, throughout his life, Hemmings maintained categorically that Britten's conduct with him was beyond reproach at all times. Hemmings had earlier played the title role in Britten's The Little Sweep (1952), which was part of Britten's Let's Make An Opera! children's production.
Britten's interest in Hemmings ceased very abruptly, from the moment his voice broke, which occurred unexpectedly while singing the aria "Malo" during a performance of The Turn of the Screw in 1956 in Paris. Britten was furious, waved Hemmings away, and never had any further contact with him.
Hemmings then moved on to acting and directing in film. He made his first film appearance in the drama film The Rainbow Jacket (1954), but he first became well known as a pin-up and film star in the mid-1960s.
Antonioni, who detested the "Method" way of acting, sought to find a fresh young face for the lead in his next production, Blowup. Then, he found Hemmings, at the time acting in small stage theatre in London, although at their first meeting, Antonioni told Hemmings, "you look wrong. You're too young". Hemmings was offered the part of the protagonist after actor Sean Connery turned the role down because Antonioni would not show him the full script, but only a seven-page treatment stored in a cigarette packet.
Following Blowup, Hemmings appeared in a string of major British films, including the musical film Camelot (1967), the war film The Charge of the Light Brigade (1968), the science-fiction film Barbarella (1968) and in the title role, the epic film Alfred the Great (1969).
Around 1967, Hemmings was briefly considered for the role of Alex in a planned film version of Anthony Burgess's novel A Clockwork Orange (1962), which was to be based on a screen treatment by satirist Terry Southern and British photographer Michael Cooper. Cooper and the Rolling Stones rock group were reportedly upset by the move and it was decided to return to the original plan in which Mick Jagger, the lead vocalist of the Rolling Stones, would play Alex, with the rest of the Stones as his droog gang; the production was shelved after Britain's chief censor, the Lord Chamberlain, indicated that he would not permit it to be made.
Hemmings directed the drama film The 14 (1973), which won the Silver Bear at the 23rd Berlin International Film Festival. He appeared in the Italian giallo film Profondo Rosso (also known as Deep Red or The Hatchet Murders) (1975) directed by Dario Argento. In 1977 he appeared as Eddy in the film Islands in the Stream, an adaptation of Hemingway's novel of the same name.
He directed David Bowie and Marlene Dietrich in the drama film Schöner Gigolo, armer Gigolo (also known as Just a Gigolo) (1978). The film was poorly received, with Bowie describing it as "my 32 Elvis Presley films rolled into one". Hemmings directed the horror film The Survivor (1981), based on James Herbert's 1976 novel of the same name, starring Robert Powell and Jenny Agutter.
Throughout the 1980s, he also worked extensively as a director on television programmes including the action-adventure drama series Quantum Leap (e.g., the series premiere); the crime series Magnum, P.I. (in which he also played characters in several episodes); and two action-adventure series The A-Team and Airwolf (in which he also played the role of Doctor Charles Henry Moffet, twisted creator of Airwolf, in the pilot and the second-season episode "Moffett's Ghost" – a typographical error by the studio's titles unit). He once joked, "People thought I was dead. But I wasn't. I was just directing The A-Team." He directed the thriller film Race for the Yankee Zephyr (1981), which stars Ken Wahl, Lesley Ann Warren, Donald Pleasence and George Peppard.
Hemmings also directed the puzzle-contest video Money Hunt: The Mystery of the Missing Link (1984). He directed the television film The Key to Rebecca (1985), an adaptation of Ken Follett's 1980 novel of the same name. He also briefly served as a producer on the NBC crime-drama television series Stingray.
Hemmings played a vindictive cop in the docudrama film Beyond Reasonable Doubt (1980) about Arthur Allan Thomas (portrayed by John Hargreaves), a New Zealand farmer jailed for the murder of Harvey and Jeannette Crewe, but later pardoned. He directed the drama film Dark Horse (1992) and as an actor returned to the voyeuristic preoccupations of his Blowup character with a plum part as the Big Brother-esque villain in the season-three opener for the television horror anthology series Tales From the Crypt.
In later years, he had roles including appearing as Cassius in the historical epic film Gladiator (2000), with Russell Crowe, as well as appearing in the drama film Last Orders (2001) and the spy film Spy Game (2001). He appeared as Mr. Schermerhorn in the historical film Gangs of New York (2002), directed by Martin Scorsese.
His final screen appearances included the science-fiction action film, Equilibrium (2002), shortly before his death, as well the superhero film The League of Extraordinary Gentlemen (2003), with Sean Connery and as Frank Sinatra's attorney in the 2003 Australian film The Night We Called It a Day, a comedy based on true events. He also appeared in the horror film Blessed (2004) with Heather Graham, which was dedicated to him in his memory after a fatal heart attack while on set.
In 1967, Hemmings recorded a pop single, "Back Street Mirror" (written by Gene Clark), and a studio album, David Hemmings Happens, in Los Angeles. The album featured instrumental backing by several members of the Byrds, and was produced by Byrds' mentor Jim Dickson.
In the 1970s, he was jointly credited with former Easybeats members Harry Vanda and George Young as a co-composer of the song "Pasadena". The original 1973 recording of this song – the first Australian hit for singer John Paul Young – was produced by Simon Napier-Bell, in whose SNB Records label Hemmings was a partner at the time.
Hemmings also later provided the narration for Rick Wakeman's progressive-rock album Journey to the Centre of the Earth (1974) – an adaptation of Jules Verne's science-fiction novel A Journey to the Center of the Earth (1864) – which was recorded live.
He starred as Bertie Wooster in the short-lived Andrew Lloyd Webber musical, Jeeves (1975).
After his death his autobiography, Blow Up... and Other Exaggerations – The Autobiography of David Hemmings, was published in 2004.
He was married four times: to Genista Ouvry (1960–1967), actress Gayle Hunnicutt (1968–1975), Prudence de Casembroot (1976–1997), and Lucy Williams (2002 to his death). Hemmings met Hunnicutt while he was in America promoting Blowup, by which time his marriage to Ouvry was over. At their outdoor wedding, Henry Mancini conducted an orchestra and the Mamas and the Papas performed next to a swimming pool filled with doves dyed puce. Of his relationship with Hunnicutt, Hemmings remarked, "We were the poor man's Taylor and Burton". Their marriage ended when Hunnicutt discovered Hemmings' affairs with actress Samantha Eggar, his co-star in The Walking Stick (1970), and his secretary Prudence de Casembroot. During his subsequent marriage to Prudence de Casembroot, Hemmings continued his infidelities with, among others, Tessa Dahl, the daughter of Roald Dahl. Six children came from the four marriages.
Hemmings was an active supporter of liberal causes, and spoke at a number of meetings on behalf of the Liberal Party.
Hemmings died at age 62 of a heart attack, in Bucharest, Romania, on the film set of Blessed (working title: Samantha's Child) after playing his scenes for the day.
A funeral service was held for him at St. Peter's Church, in the town of Calne in the county of Wiltshire, where he had resided in his final years. His body was buried in the church's graveyard.The 14 (1973)
Just a Gigolo (1978)
Race for the Yankee Zephyr (1981)
The Survivor (1981)
The Key to Rebecca (1985)
Down Delaware Road (1988)
Dark Horse (1992)
Passport to Murder (1993)
Christmas Reunion (1994)
Lone Justice: Showdown at Plum Creek (1996)