Wills's father, Alaric Willys, was a captain in the British Army. Her mother, Anna, was a housewife.
Wills gained her first role at the age of 11 while she was living on a houseboat in Bray, Berkshire. The film was called Child's Play (1954) and she gave the £9 fee to her mother. Deciding she wanted to be an actress she then studied drama at the Arts Educational School and RADA in London and quickly became one of the busiest actresses of her generation, early roles included an appearance as Roberta in the second TV version of The Railway Children in 1957. Her other film roles included appearances in Some People (1962) and The Pleasure Girls (1965).
Her other television credits include appearances in The Avengers and as Evelyn in Strange Report (1969–70). She left the latter series when it was planned to switch filming to Hollywood (though that plan fell through).
In 1966 she took the role of Polly in Doctor Who. She appeared in the show until 1967 alongside William Hartnell and then Patrick Troughton. Her favourite story was The Smugglers.
In October 2013 she recorded an abridged version of Who's There?, a biography of William Hartnell written by his granddaughter, Jessica Carney.
In November 2013 she appeared in the one-off 50th anniversary comedy homage The Five(ish) Doctors Reboot.
She has been a popular guest at Dr Who conventions, and has been employed by the BBC and Big Finish to record various audio and DVD projects related to the show.
The first volume of her autobiography, Self Portrait, was published in 2007 by Hirst Books and a second volume, Naked, followed in 2009. Her latest book, Anneke Wills - In Focus, was published in May 2012 by Fantom Films.
At 17 she began a relationship with Anthony Newley while working on the TV series The Strange World of Gurney Slade. Newley fathered Wills' first child, but left her to marry Joan Collins. During the 1960s Wills spent much of her time at the famous Troubadour Coffee Shop and the Establishment, and was part of the so-called "Chelsea Set".
Wills married actor Michael Gough in 1962; the couple divorced in 1979. In 1970, she gave up acting and moved to Norfolk, throwing herself into motherhood and gardening. She remarried twice. She left the UK in 1980 and lived in various places in the 16 years afterwards, including in Laos, Vietnam and India in the early 1980s, in the USA from 1983–1986, and in Canada from 1986–1996. She returned to live in the UK in 1996.