Born in Salford she was friends at school with future playwright Shelagh Delaney. She trained at RADA where she gained an Honours Diploma and her first part was in repertory theatre in Richmond, followed by Bolton and then St. Anne's where she met Arthur Leslie in a production of Pygmalion with her playing the part of Eliza and Mr Leslie as Alfred, her father. Both of them were asked to audition of Coronation Street while playing these roles and Ms Hargreaves felt that she got part on the strength of the way she said "Charming" in an off-hand manner typical of Christine Hardman.
At one time she was married to Klaus Voormann, a friend of The Beatles who designed the cover of their 1966 album Revolver. After Coronation Street she appeared many times in television and is particularly remembered for her starring role in The Spongers (1978), an acclaimed Play for Today written by Jim Allen and directed by Roland Joffe.
She died of a brain tumour in August 1984, aged 45.