Newley was born in the London district of Hackney, the son of Frances Grace Newley and George Kirby, a shipping clerk. He had five siblings, Maxene (b. 1926), John (b. 1927), Joanne (1928–1965), Linda (b. 1929) and Belinda (b. 1932). He was Jewish through his maternal grandmother. His parents, who had never married, separated during his early childhood, and his aunt and uncle brought him up through unofficial adoption. During the Second World War he was evacuated to a foster home in the country area safe from the Blitz aerial bombing attacks on London.
Newley's first major film roles were Dusty Bates in The Adventures Of Dusty Bates (1947) and as Dick Bultitude in Peter Ustinov's Vice Versa (1948) followed by the Artful Dodger in David Lean's Oliver Twist (1948), based on the Charles Dickens novel. He made a successful transition from child star to actor in British films of the 1950s, broken by his national Service. During the 1950s, he appeared in many British radio programmes and for a time appeared as Cyril in Floggits starring Elsie and Doris Waters. But it was probably the film Idol on Parade (1959) that most changed his career direction. In the film he played a rock singer called up for national service; the story was somewhat inspired by Elvis Presley having recently been drafted for army Service in the United States. The 1958 film No Time to Die (aka Tank Force) cemented Newley's position as a leading screen actor.
His second marriage to Ann Lynn from 1956 to 1963 ended in divorce. A son, Simon, was born to them but died in infancy from a congenital infirmity. He then was married to the Actress Joan Collins from 1963 to 1970. The couple had two children, Tara Newley and Sacha (Alexander) Newley. Tara became a broadcaster in Britain and Sacha is a renowned portrait Artist based in New York City and represented by four paintings in the National Portrait Gallery in Washington. Newley's fourth wife was former air hostess Dareth Rich, and they also had two children, Shelby and Christopher. In an episode of Angela and Friends (Sky One), Tara Newley also mentioned another sister, a third living daughter of Newley.
Amongst the many compilations issued are Anthony Newley: The Decca Years (1959–1964), Once in a Lifetime: The Anthony Newley Collection (1960–71), and Anthony Newley's Greatest Hits (Deram). In May 2010, Stage Door Records released a compilation of unreleased Newley recordings entitled 'Newley Discovered'. The album produced with the Anthony Newley Society and Newley's family contains the concept recordings for Newley's self-penned film musicals Can Heironymus Merkin Ever Forget Mercy Humppe and Find True Happiness?, Willy Wonka & the Chocolate Factory and Mr. Quilp.
He wrote ballads, many with Leslie Bricusse, that became signature hits for Sammy Davis Jr., Shirley Bassey and Tony Bennett. During the 1960s he also added his greatest accomplishments on the London West End theatre and Broadway theatre stage, in Hollywood films and British and American television.
In 1963, Newley had a hit comedy album called Fool Britannia!, the result of improvisational satires of the British Profumo scandal of the time by a team of Newley, his then-wife Joan Collins and Peter Sellers. It peaked at number 10 in the UK Albums Chart in October 1963.
Newley played Matthew Mugg in the original Doctor Dolittle (a difficult experience in part because of the hostility he endured from the lead actor, Rex Harrison) and he also played the repressed English businessman opposite Sandy Dennis in the original Sweet November. He hosted Lucille Ball's character on a whirlwind tour of London in Lucy in London (1966). He performed in the autobiographical, Fellini-esque and X-rated Can Heironymus Merkin Ever Forget Mercy Humppe and Find True Happiness?, which he also directed and co-wrote with Herman Raucher. He appeared as Quilp in Mister Quilp (1975) (based on Dickens's The Old Curiosity Shop), for which he composed some songs ('Love Has the Longest Memory of All'). His last feature role, in the cast of the long-running British TV soap opera EastEnders, was to have been a regular role, but Newley had to withdraw after a few months when his health began to fail.
In the 1970s he remained active, particularly as a Las Vegas and Catskills Borscht Belt resort performer, game show panelist (such as on Hollywood Squares) and talk show guest, but his career had begun to flounder. He had taken risks that eventually led to his downfall in Hollywood. Throughout the 1980s and 1990s he worked to achieve a comeback. He briefly appeared on Late Night with David Letterman (when in town to be inducted into the Songwriters' Hall of Fame) to sing the theme to "Viewer Mail". He staged a successful American tour of his Stop The World – I Want To Get Off in 1986–87. The production co-starred a then unknown Suzie Plakson, whom Newley had discovered. The tour yielded her some strong notices and led to a steady career on stage and television. In 1985, he was also featured as the Mad Hatter in Irwin Allen's all-star television adaptation of Alice in Wonderland. In his later years as a mature singer Newley recorded songs from Fiddler on the Roof and Scrooge. He enjoyed his final popular success onstage when he starred in the latter musical which showed in London and toured British cities including Liverpool, Birmingham, Bristol and Manchester, in the 1990s. At the time of his death he had been working on a musical of Shakespeare's Richard III. He died of renal cancer at the age of 67, soon after he had become a grandfather.
Despite the fact that such compositions as "What Kind of Fool Am I?" and "The Candy Man" (a US Number One single for Sammy Davis Jr. and the Mike Curb Congregation in 1972) became international hits, Newley had less chart success in the United States as a recording Artist, charting on the Billboard Hot 100 with four singles from 1960–62, none reaching higher than number 67. However, he later had a number 12 hit on the Adult Contemporary charts in 1976 with "Teach the Children".
In recognition of his creative skills and body of work, Newley was elected to the Songwriters' Hall of Fame in 1989.
Newley died on 14 April 1999, in Jensen Beach, Florida, from renal cancer at the age of 67. He had first been diagnosed with cancer in 1985, and it returned in 1997 and spread to his lungs and liver. He was said to have died in the arms of his companion, the designer Gina Fratini. He was survived by his five children, a granddaughter Miel, and his mother Grace, then aged 96, who has subsequently died. Since then two more grandchildren have been born: Weston (Tara's second child) and Ava Grace (Sacha's first, with his wife Angela Tassoni).
Newley's life is the subject of a biography by Garth Bardsley called Stop the World (London: Oberon, 2003).
Pure Imagination: The World of Anthony Newley and Leslie Briccuse, devised and directed by Bruce Kimmel, opened at the Pacific Resident Theatre in Venice, California, on 7 December 2013.
