It was a role he relished and he often returned to it over a period of four decades.
He was a consummate character actor who took on a wide variety of roles on stage, screen and television.
And despite playing Johnny Speight's infamous creation for such a long time, he managed to avoid being typecast as Britain's favourite bigot.
Warren Mitchell was actually born as Warren Misell on 14 January 1926 in north London.
His father, Monty, was English, while his mother Annie, who died when he was 15, was of Russian descent.
He was chosen, aged five, to play Tiny Tim in his primary school's production of A Christmas Carol but never made the stage.
His Orthodox Jewish grandmother vetoed the idea when she learned he would be breaking Jewish dietary law by eating Christmas pudding containing suet.
In later years he developed a pathological loathing of Christmas, referring to it as "all that sentimental crap".
However, his interest in acting grew and, at the age of seven, he was enrolled in Gladys Gordon's Academy of Dramatic Arts in Walthamstow, east London.
He also developed a love of football, becoming a staunch supporter of Tottenham Hotspur.
He did well at school and went on to read physical chemistry at University College, Oxford, where he met Richard Burton, who encouraged his interest in acting.
They joined the RAF together in 1944 and Mitchell was sent to Canada to train as a navigator, although the war ended before he saw active service.
Mitchell enrolled for a two-year course at the Royal Academy of Dramatic Art, spending his evenings performing with the left-wing Unity Theatre in London, where he met his wife, Connie.
Because she was an Anglican, Mitchell's Jewish father initially refused to have Connie in the house, but he eventually came round to the idea of his son marrying outside his faith.
Mitchell was an atheist for most of his life and a keen supporter of the British Humanist Association.
He changed his name in 1951 when he stood in for the DJ Pete Murray as a presenter on Radio Luxembourg.
"They said, 'You can't have a name like that, nobody's ever going to write in their request to Warren Misell'," Mitchell later explained.
By now he had become a competent character actor in straight and comedy roles, while premature baldness gave him the ability to play a wide age range.
After appearing in the popular radio show Educating Archie, he got his TV break in 1955 in a number of episodes of Hancock's Half Hour.
He became a TV regular with roles in shows such as The Avengers, Danger Man and The Saint.
He also appeared in sitcom, notably with Charlie Drake in the BBC production Drake's Progress, which ran in 1957.
By then he had already made his film debut, an uncredited role in the wartime drama The Battle of the River Plate.
It was the first of many screen appearances although, with his baldness and command of eastern European accents, he was often cast in minor roles, usually as the foreign villain.
In 1965 he got the part of Alf Ramsey in a one-off Comedy Playhouse production of Till Death Us Do Part, after Peter Sellers, Leo McKern and Lionel Jeffries had turned it down.
The BBC launched a series in 1966 with the leading character's name changed to Alf Garnett, and the programme ran until 1975, with more than 50 episodes.
The show highlighted the pressures felt by the white working class at a time of great social change in Britain.
Mitchell later returned as Alf Garnett in the series In Sickness and in Health.
The show broke a number of taboos, with a high level of swearing and insulting references to racial minorities, and was condemned by TV clean-up campaigner Mary Whitehouse as a sign of the BBC's declining moral standards.
The irony of a left-wing, Jewish, Spurs supporter playing a Conservative-voting West Ham fan was not lost on Mitchell, although he became concerned that some of his audience failed to recognise the show as satire.
He recalled an exchange with a fellow Tottenham fan who had come up to congratulate him on "having a go" at immigrants. "Actually," Mitchell tersely replied, "we're having a go at idiots like you."
Throughout the 1970s, Mitchell found time for other roles, appearing in The Sweeney and Lovejoy on TV, as well as taking a part in Terry Gilliam's feature film Jabberwocky.
He won an Olivier award for a 1979 stage appearance as Willy Loman in Arthur Miller's Death of a Salesman, a performance described by Miller himself as the finest interpretation of the part he had ever seen.
A year later, he played Shylock in a BBC TV production of The Merchant of Venice, and received much praise for his role in Harold Pinter's The Caretaker at the National Theatre.
By now he was spending a great deal of his time in Australia where Till Death Us Do Part had made him a household name, and he took up dual UK-Australian citizenship in 1988.
He had not entirely abandoned Alf, who reappeared as part of his one-man show, although an ITV-produced spin-off was cancelled at Mitchell's request after the death of Speight in 1998.
He continued his TV work, appearing in Wall of Silence in 1993, a BBC murder mystery set in a Jewish community in north London, and took the part of Barquentine in the corporation's ambitious  production of Gormenghast.
He picked up a second Olivier award for his stage performance as a nonagenarian furniture dealer in a 2004 production of Arthur Miller's The Price.
Despite battling with pain from nerve damage caused by a viral attack in the late 1980s, and a stroke in later years, Mitchell continued to take on gruelling roles.
At the age of 82 he was performing in the West End of London as a retired dry-cleaner in Jeff Baron's portrait of Jewish-American life, Visiting Mr Green.
The advancing years, coupled with ill health, brought increasing irascibility, almost as if the Alf character were struggling to re-emerge.
He continually bemoaned what he saw as the dumbing-down of television, claiming it no longer produced either great comedy or culture.
And he spearheaded a campaign against outdoor concerts near his home in Hampstead London after the organisers switched from classical music to more populist fare.
Mitchell was once asked for his idea of perfect happiness. "Play three sets of tennis, and win of course, take the family for a sail in the afternoon, and watch Spurs beat Arsenal 6-0 in the evening."
Warren Mitchell never completely distanced himself from his most famous character, Alf Garnett.