Watt was born in Greenock, Scotland, in 1965. She attended the Glasgow School of Art from 1983 to 1988. In 1987, the artist won the John Player Portrait Award, the recognition from which lead her to paint a portrait of Queen Elizabeth II. Originally known for her figurative work, Watt made a marked shift to painting fabrics, and was awarded the ACE Prize for her painting Still in 2004. Her work is in numerous public collections including the Uffizi, Florence, National Portrait Gallery, London and the National Galleries of Scotland, Edinburgh.