She studied at the Bristol Old Vic Theatre School in the 1960s. Her performance in the title role of Marie Curie (1977) first brought her to wide attention. In 1978 she performed the title role Édith Piaf for Pam Gems's play Piaf, directed by Howard Davies for the Royal Shakespeare Company, in Stratford-upon-Avon and in London at the Warehouse Theatre, Covent Garden in 1979.
She was married to Director Roland Joffé from 1974 to 1980; they had one son, Screenwriter and Director Rowan Joffé (born 1973). Following their divorce, she was for a time the partner of actor Michael Pennington.
In 2000 while working in France, Lapotaire suffered a cerebral haemorrhage. She writes about her recovery in Time Out of Mind.
