Miriam Margolyes was born in Oxford, England, the only child of Ruth and Joseph Margolyes. She attended Newnham College, Cambridge, where she read English and began acting, appearing in Cambridge Footlights productions.
Miriam has become known for her TV roles in Blackadder opposite Rowan Atkinson and in numerous film roles including Mrs Mingott in Martin Scorsese's The Age of Innocence (1993); Aunt Sponge in James and the Giant Peach (1996); and Nurse in Baz Luhrmann's Romeo + Juliet (1996). She also played Professor Sprout in two of the film adaptions of the Harry Potter novels.
A lifelong admirer of the works of Charles Dickens, she won theatrical acclaim for her one-woman show, Dickens' Women, performing 23 characters from Dickens' novels.