Della Jones is admired as one of the foremost bel canto mezzo-sopranos of her generation, though her repertoire extends from Nerone in Monteverdi's The Coronation of Poppea to Dolly in Hamilton's Anna Karenina, a role she created in the work's 1991 premiere. She has also taken the occasional foray into Gilbert and Sullivan and other musicals. She has taken particular interest in forgotten bel canto operas, starring in many revivals and world-premiere recordings. She studied singing at the Royal College of Music, where she won the Kathleen Ferrier Memorial Prize, and in Geneva, where she made her opera debut as Feodor in Mussorgsky's Boris Godunov in 1970. In 1977, she began a long association with the English National Opera. She made her Covent Garden debut in 1983 as the female cat in Ravel's L'enfant et les sortilèges. In 1993, she starred in the famous Last Night at the Proms, and in 1997 sang during the ceremonies marking the transition of Hong Kong from British to Chinese rule.