Bates was born at the Queen Mary Nursing Home, Darley Abbey, Derby, England, on 17 February 1934, the eldest of three sons of Florence Mary (née Wheatcroft), a housewife and a Pianist, and Harold Arthur Bates, an insurance broker and a Cellist. They lived in Allestree, Derby, at the time of Bates' birth, but briefly moved to Mickleover before returning to Allestree.

Bates's stage debut was in 1955, in You and Your Wife, in Coventry. In 1956 he made his West End debut as Cliff in Look Back in Anger, a role he had originated at the Royal Court and which made him a star. He also played the role on television (for the ITV Playhouse) and on Broadway. In the late 1950s Bates appeared in several plays for television in Britain. In 1960 he appeared in The Entertainer opposite Laurence Olivier, his first film role. Bates worked for the Padded Wagon Moving Company in the early 1960s while acting at the Circle in the Square Theatre in New York City. Throughout the 1960s he starred in several major films including Whistle Down the Wind (1961), A Kind of Loving (1962), Zorba the Greek (1964), Philippe de Broca's King of Hearts (1966), Georgy Girl (1966), Far From the Madding Crowd (1967) and the Bernard Malamud film The Fixer (1968), which earned him an Academy Award nomination for Best Actor. In 1969 he starred in Women in Love.

In the later years of his life, Bates had a relationship with the Welsh Actress Angharad Rees and in the last years, his companion was his lifelong friend, Actress Joanna Pettet, his co-star in the 1964 Broadway play Poor Richard. They divided their time between New York and London.

He is also known for his performance with Anthony Quinn in Zorba the Greek, as well as his roles in King of Hearts, Georgy Girl, Far From the Madding Crowd and The Fixer, for which he received an Academy Award nomination for Best Actor. In 1969, he starred in the Ken Russell film Women in Love with Oliver Reed and Glenda Jackson.

Bates was married to Actress Victoria Ward from 1970 until her death in 1992, although they had separated many years earlier. They had twin sons, born in November 1970, the actors Benedick Bates and Tristan Bates. Tristan died following an asthma attack in Tokyo in 1990. Other sources report Tristan died of a heroin overdose in a public toilet.

Bates was handpicked by Director John Schlesinger (with whom he had previously worked on A Kind of Loving and Far From The Madding Crowd) to play the starring role of Dr. Daniel Hirsh in the film Sunday Bloody Sunday (1971). Bates was held up filming The Go-Between (1971) for Director Joseph Losey, and had also become a Father around that time, and so he had to refuse the role. (The part then went first to Ian Bannen, who balked at kissing and simulating sex with another man, and then to Peter Finch who earned an Academy Award nomination for the role.)

Around this time he appeared as Col. Vershinin in the National Theatre's film of Three Sisters, directed by and co-starring Laurence Olivier. He later worked with Olivier for television in the Laurence Olivier Presents version of Harold Pinter's The Collection (1976) and A Voyage Round My Father (1982).

Bates starred in such international films as An Unmarried Woman (1978) and Nijinsky (1980), and also played Bette Midler's ruthless Business manager in the film The Rose (1979). On television, his parts included Michael Henchard, the ultimately-disgraced lead in The Mayor of Casterbridge – which he described as his favourite role – in the serial adaptation by Dennis Potter (1978). He played two diametrically-opposed roles in An Englishman Abroad (1983), as Guy Burgess, a member of the Cambridge spy ring exiled in Moscow, and in Pack of Lies (1987), as a British Secret Service agent tracking several Soviet spies. He continued working in film and television in the 1990s, including the role of Claudius in Mel Gibson's version of Hamlet (1990), though most of his roles in this era were more low-key.

On stage Bates had a particular association with the plays of Simon Gray, appearing in Butley, Otherwise Engaged, Stage Struck, Melon, Life Support and Simply Disconnected, as well as the film of Butley and Gray's TV series Unnatural Pursuits. In Otherwise Engaged, his co-star was Ian Charleson, who became a friend, and Bates later contributed a chapter to a 1990 book on his colleague after Charleson's early death.

Bates had numerous homosexual relationships, including those with actor Nickolas Grace and Olympic skater John Curry. In 1994, Curry died from AIDS in Bates's arms. Even after homosexuality was partially decriminalised in Britain in 1967, Bates rigorously avoided interviews and questions about his personal life, and even denied to his male lovers that there was a homosexual component in his nature. While throughout his life Bates sought to be regarded as a ladies' man or at least as a man who, as an actor, could appear attractive to and attracted by women, he also chose many roles with an aspect of homosexuality or bisexuality, including the role of Rupert in the 1970 film Women in Love and the role of Frank in the 1988 film We Think the World of You.

Bates was made a Commander of the Order of the British Empire (CBE) in 1996, and was knighted in 2003. He was an Associate Member of RADA and was a patron of The Actors Centre, Covent Garden, London, from 1994 until his death in 2003.

In 2001 Bates joined an all-star cast in Robert Altman's critically acclaimed period drama Gosford Park, in which he played the butler Jennings. He later played Antonius Agrippa in the 2004 TV film Spartacus, but died before it premiered. The film was dedicated to his memory and that of Writer Howard Fast, who wrote the original novel that inspired the film Spartacus by Stanley Kubrick.

Bates had undergone a hip replacement shortly before being diagnosed with inoperable pancreatic cancer in January 2003. He suffered a stroke later that year, and died in December after going into a coma. He is buried at All Saints' Church, Bradbourne.

The posthumous publication of Donald Spoto's 2007 book, Otherwise Engaged: The Life of Alan Bates, is the only authorised biography of Alan Bates. It was written with the full and complete cooperation of his sons Benedick and Martin, and includes more than one hundred interviews with people such as Michael Linnit and Rosalind Chatto.

Source: "Alan Bates". IMDb. Retrieved 3 April 2014.