Bron was born Eleanor Bronstein in Stanmore, London into a family with an Eastern European Jewish background. Her father shortened the surname to Bron when founding Bron's Orchestral Service. She was educated at the North London Collegiate School and Newnham College, Cambridge.Bron was the partner of the architect Cedric Price until his death in 2003. They had no children. Her elder brother is the record producer Gerry Bron.
Bron began her career in the Cambridge Footlights revue of 1959, entitled The Last Laugh, in which Peter Cook also appeared. The addition of a female performer to the Footlights was a departure, having been until that point all-male, with female characters portrayed in drag. As with many others of the British satire boom, participation in the Footlights was a springboard to a long career in British comedy as both a writer and performer.
Her film appearances include the role of Ahme in the Beatles film, Help! (her given name inspired Paul McCartney while composing "Eleanor Rigby"). Other roles included the doctor who grounds the Lothario played by Michael Caine in Alfie, the unattainable Margaret Spencer in Peter Cook and Dudley Moore's film Bedazzled, and Hermione Roddice in Ken Russell's Women in Love. She appears in the film Two for the Road alongside Albert Finney, Audrey Hepburn and William Daniels. More recently she has appeared in the film adaptations of A Little Princess, The House of Mirth, Black Beauty and in Wimbledon.
Eleanor Bron's earliest work for television included appearances on Not So Much a Programme More a Way of Life, My Father Knew Lloyd George and BBC-3, where she performed in sketches with John Fortune; they had already worked together at Peter Cook's Establishment Club. Later, her work included such programmes as Where Was Spring? (1969) and After That, This (1975) — the one with the "egg" timer in the opening credits.
She collaborated with novelist and playwright Michael Frayn on the BBC programmes Beyond a Joke (1972) and Making Faces (1975).
She appeared in a 1982 episode ("Equal Opportunities") of the BBC series Yes Minister, playing a senior civil servant in Jim Hacker's Department. Hacker plans to promote her to strike a blow for equal opportunities.
Bron appeared in a brief scene in the BBC science fiction television series Doctor Who serial City of Death alongside John Cleese as art critics in Denise Rene's art gallery in Paris. The pair are admiring the TARDIS, thinking it to be a piece of art, when the Doctor (Tom Baker), Romana (Lalla Ward) and Duggan (Tom Chadbon) rush into it and it dematerialises. Bron's character, believing this to be part of the work, states that it is "Exquisite, absolutely exquisite!"
She also appeared as an art critic in a parody of an Andy Warhol documentary on the BBC sketch comedy show French and Saunders.
Later, she had a more substantial guest role in another Doctor Who television serial, 1985's Revelation of the Daleks. She has more recently also appeared in an audio drama based on Doctor Who by Big Finish Productions, (Loups-Garoux), in which she plays the part of wealthy heiress Ileana de Santos.
She plays, through flashback, the recurring character of Patsy's mother in the sitcom, Absolutely Fabulous, an exuberantly horrible woman who "scattered bastard babies across Europe like a garden sprinkler". After giving birth, she would always say "Now take it away! And bring me another lover."
In 1975 she appeared in the West End musical The Card. Throughout the 1980s she appeared in Amnesty International's Secret Policeman's Balls live benefit shows, working alongside Peter Cook and Rowan Atkinson. In 2005 she appeared in the Liverpool Empire Theatre in the musical play Twopence To Cross The Mersey. She appeared in the role of an abbess in Howard Brenton's play In Extremis, staged in Shakespeare's Globe in 2007. She has also recently appeared in the dramatized version of Pedro Almodovar's film All About My Mother which opened at the Old Vic theatre in the late summer of 2007.
Bron also gave the premiere performance of The Yellow Cake Revue, a series of pieces for voice and piano written by Peter Maxwell Davies in protest against uranium mining in the Orkney Islands.
In 1985, Bron was selected for her authoritative tone to become "the voice of BT" and can still be heard on various error messages such as "Please hang up and try again" and "The number you have dialled has not been recognised".
In 2001 and 2002 she has appeared in the BBC radio comedy sketch show, The Right Time, along with Graeme Garden, Paula Wilcox, Clive Swift and Neil Innes. Another notable radio appearance was in The Further Adventures of Sherlock Holmes in the 2002 episode "The Madness of Colonel Warburton".
In 2001 she played the great-grandmother in the seven-part ITV series Gypsy Girl, based on books by Elizabeth Arnold.
In 2006 she narrated the BBC Radio 4 adaptation of the Craig Brown book 1966 and All That. Other work includes a recorded tour of Sir John Soane's Museum in London, England.
In April 2010, Bron, along with Ian McKellan and Brian Cox, appeared in a series of TV advertisements to support Age UK the charity recently formed from the merger of Age Concern and Help the Aged. All three actors gave their time free of charge.
As a writer
She is the author of several books, including Life and Other Punctures, an account of bicycling in France and Holland on an early Moulton bicycle; and The Pillow Book of Eleanor Bron.
She is mentioned in the Yo La Tengo song "Tom Courtenay", in the line "dreaming 'bout Eleanor Bron, in my room with the curtains drawn...".