Sanders was born in Saint Petersburg, Russian Empire, at number 6 Petrovski Ostrov. His English parents were Henry Sanders (1873–1961) and Margaret Sanders (1875–1967). Actor Tom Conway (1904–1967) was his elder brother. His younger sister, Margaret Sanders, was born in 1912. The future actor was 11 when, in 1917, at the outbreak of the Russian Revolution, the family returned toEngland. Like his brother, he attended Bedales School, Brighton College, a boys' independent school in Brighton, Sussex, then went on to Manchester Technical College. After graduation, he worked at an advertising agency, where the company secretary, aspiring actress Greer Garson, suggested he take up a career in acting.
Sanders made his British film debut in 1929, Seven years later, after a series of British films, his first role in an American production was Lloyd's of London (1936) as Lord Everett Stacy. His smooth, upper-crust English accent and sleek British manner, along with a suave, snobbish and somewhat threatening air, put him in demand for American films throughout the following decade. He played supporting roles in A-pictures productions such as Alfred Hitchcock's Rebecca (1940), in which he and Judith Anderson played cruel foils to Joan Fontaine's character. He had leading roles in somewhat lower-budget pictures such as Rage in Heaven (1941). He also played the lead in both The Falcon and The Saint film series. In 1942, Sanders handed the Falcon role to his brother Tom, in The Falcon's Brother. The only other film in which the two siblings appeared together was Death of a Scoundrel (1956), in which they also played brothers.
Sanders played Lord Henry Wotton in the film version of The Picture of Dorian Gray (1945) and he was the third lead behind Gene Tierney and Rex Harrison for The Ghost and Mrs. Muir (1947). Sanders gave one of his most critically noted performances, starring with Angela Lansbury in director Albert Lewin's little-known film The Private Affairs of Bel Ami (also 1947) taken from an 1885 novel by Guy de Maupassant. He and Lansbury also featured in Cecil B. deMille's biblical epic Samson and Delilah (1949).
Drawing his greatest popular and commercial success as the acerbic, cold-blooded theatre critic Addison DeWitt, in All About Eve(1950), he won an Academy Award for Best Supporting Actor for his performance. He then starred as Sir Brian de Bois-Guilbert in the 1952 film Ivanhoe, dying in a duel with Robert Taylor after professing his love for Jewish maiden Rebecca, played by Elizabeth Taylor.
Sanders went into television with the successful series The George Sanders Mystery Theater. He played an upper-crust English villain, G. Emory Partridge, in the The Man From U.N.C.L.E. episode "The Gazebo in the Maze Affair" (1965) and reprised the role later in that same year in "The Yukon Affair". He also portrayed Mr. Freeze in two episodes of the live-action Batman TV series which were shown in February 1966. Sanders voiced the malevolent Shere Khan in the Walt Disney production of The Jungle Book (1967). During the production of The Jungle Book's soundtrack, Sanders was unavailable to provide the singing voice for Shere Khan during the final recording of the song, "That's What Friends Are For" despite being an accomplished singer. Mellomen member Bill Lee was called in to substitute for Sanders and can be heard on the soundtrack. In the film, however, all the singing was done live and Sanders provided Khan's singing voice.
Sanders' smooth voice, urbane manner and upper-class British accent inspired Peter Sellers' character "Hercules Grytpype-Thynne" in the BBC radio comedy series The Goon Show (1951–60). In 1964, Sellers and Sanders appeared together in the Pink Panther sequel A Shot in the Dark. In 1969, he had a supporting role in John Huston's The Kremlin Letter, in which his first scene showed him dressed in drag and playing piano in a snooty San Francisco gay bar. One of Sanders' final screen roles was in Doomwatch (1972), a feature film version of a contemporary BBC television series .
Two ghostwritten crime novels were published under his name to cash in on his fame. The first was Crime on My Hands (1944), written in the first person and mentioning his "Saint" and "Falcon" films. This was followed by Stranger at Home in 1946. Both were actually written by female authors: the former by Craig Rice, and the latter by Leigh Brackett.
In 1958, Sanders recorded an album called The George Sanders Touch: Songs for the Lovely Lady. The album was released by ABC-Paramount Records, and carried lush string arrangements of romantic ballads, crooned by Sanders in a fit baritone/bass (spanning from low to middle C), including "Such is My Love", a song of Sanders' own composition. After going to great lengths, he got himself signed to sing in South Pacific but was overwhelmed with anxiety over the role and quickly dropped out. Sanders' singing voice can be heard inCall Me Madam (1953). He also signed on for the role of Sheridan Whiteside in the stage musical Sherry! (1967), based on the Kaufman–- Hart play The Man Who Came to Dinner, but he found the ongoing stage production highly demanding. He quit when his wife Benita Hume discovered she had terminal bone cancer.
During the production of The Jungle Book, Sanders, who voiced Shere Khan, was unavailable to provide the singing voice for his character during the finalized recording of the song, "That's What Friends Are For" despite being an accomplished singer. According toRichard Sherman, Mellomen member Bill Lee was called in to substitute for Sanders.
On 27 October 1940, Sanders married Susan Larson; they divorced in 1949. From later that year until 1954, Sanders was married to Hungarian actress Zsa Zsa Gabor (with whom he starred in the 1956 film Death of a Scoundrel after their divorce). On 10 February 1959, Sanders married actress Benita Hume, widow of actor Ronald Colman. She died in 1967, the same year Sanders' brother Tom Conway died of liver failure. Sanders had become distant from his brother a decade before due to Conway's drinking problem.
His autobiography, Memoirs of a Professional Cad, was published in 1960 and gathered critical praise for its wit. Sanders suggested the title A Dreadful Man for his biography, which was later written by Sanders' friend Brian Aherne and published in 1979.
Sanders' last marriage was on 4 December 1970, to Magda Gabor, the elder sister of his second wife. This marriage lasted only six weeks, after which he began drinking heavily.
In his later years, Sanders suffered from dementia, worsened by waning health. He can be seen teetering in his last films, owing to a loss of balance. According to Aherne's biography, he also had a minor stroke. Sanders could not bear the notion of losing his health or needing help from someone else, and he became deeply depressed. At about this time, Sanders found he could no longer play his grand piano, which he dragged outside and smashed with an axe. His last girlfriend, who was Mexican and much younger than he, persuaded Sanders to sell his beloved house in Majorca, Spain, which he later bitterly regretted. From then on, he drifted.
On 23 April 1972, Sanders checked into a hotel in Castelldefels, a coastal town near Barcelona. He was found dead two days later, having gone into a cardiac arrest. He had taken five bottles of the barbiturate Nembutal. Sanders was 65 years old. The death was officially a suicide since he left behind three gentlemanly suicide notes, which read:
Dear World, I am leaving because I am bored. I feel I have lived long enough. I am leaving you with your worries in this sweet cesspool. Good luck. (with his signature under the message)
Sanders' body was returned to Britain for funeral services, after which it was cremated and the ashes were scattered in the English Channel. David Niven wrote in his own autobiography, The Moon's a Balloon (1972), that in 1937 his friend George Sanders had predicted he would commit suicide when he was 65, and in his 50s, he appeared depressed since his marriages had failed and several tragedies had befallen him.