Born in Hereford, Herefordshire in 1919, Reid was the daughter of Scottish parents, and grew up in Manchester, where she attended Withington and Levenshulme High Schools.

Leaving school at 16, she made her debut in 1936 as a music hall performer at the Floral Hall, Bridlington. Before and during the Second World War, she took part in variety shows and pantomimes. She had no formal training but later appeared at the Royal National Theatre in London as a comedy Actress. Her first big success came in the BBC radio show Educating Archie as naughty schoolgirl Monica and later as the Brummie, "Marlene."

She was the subject of This Is Your Life in 1976 when she was surprised by Eamonn Andrews in the car park of Thames Television’s Teddington Studios.

Between 1981 and 1983, she co-presented the Children's TV programme Get up and Go for Yorkshire Television, her co - presenter "Mooncat" being a green, talking, puppet cat. Stephen Boxer was her human co-star. After she left the show it became titled simply Mooncat and Co.

In both Tinker Tailor Soldier Spy and Smiley's People, Reid played Connie Sachs. For Smiley's People she won a BAFTA for Best Actress on Television. She also wrote an autobiography, So Much Love, which was well received. She played the part of an elderly feminist and political subversive in the 1987 television drama, The Beiderbecke Tapes.

Beryl Reid died on 13 October 1996 from pneumonia and osteoporosis at a South Buckinghamshire hospital following knee surgery. She was 77 years old.

An authorized biography, Roll Out the Beryl, is due for publication by Fantom Films on 22 August 2016. Written by Kaye Crawford, it is the first biography to be written of the Actress and coincides with the twentieth anniversary of her death.