An award-winning Scottish author, she is best known for A Little Stranger (1989), Debatable Land (1994), and Wait Till I Tell You (1997). Her 2010 memoir, What to Look for in Winter, describes her progressive loss of eyesight.
She attended Girton College, Cambridge, where she earned first-class honors. She published her first novel, A Case of Knives, in 1988.
Her novel, Debatable Land, won the Guardian Fiction Prize.
She had two children with her first husband, Quentin Wallop. With her second husband, Fram Dinshaw, she had a third child.
Like fellow Scottish author, Sir Arthur Conan Doyle, McWilliam has been recognized all over the world for her literary work.