After being educated at Leighton Park School and in Paris, Bell became a Lecturer in Art History at the Department of Fine Art, King's College, University of Durham from 1952 to 1959, then became the first Professor of Fine Art at the University of Leeds from 1959 to 1967. In 1964 he was appointed Slade Professor of Fine Art at Oxford University and, in 1965, Ferens Professor of Fine Art at the University of Hull. Bell was a Professor of Art History and Theory at the University of Sussex from 1967 to 1975.
He sometimes worked as an artist - principally in ceramics - but for his career he was drawn to academia and to book-writing. Bell's biography of his famous aunt, Virginia Woolf: A Biography, 2 vols (London: Hogarth Press, 1972), won not only the James Tait Black Memorial Prize, but also the Duff Cooper Prize and the Yorkshire Post Book of the Year Award. He also wrote several books on the Bloomsbury Group and Charleston Farmhouse.
He was married to Anne Olivier Bell (née Popham). They had three children: Julian Bell, an artist and muralist; Cressida Bell, a notable textile designer; and Virginia Nicholson, the writer of Charleston: A Bloomsbury House and Garden, Among the Bohemians and Singled Out.
Quentin Bell is buried in the churchyard of St. Peter's Church, West Firle, East Sussex.