Hylton's first screen appearance came in a 1946 programmer A Girl in a Million. She quickly moved on to minor roles in films produced by Gainsborough Studios (Jassy, When the Bough Breaks) and Ealing Studios (Holiday Camp, It Always Rains on Sunday), then in 1948 landed her largest role to date, as an escaped convict's mistress in Gainsborough's My Brother's Keeper. She was cast as one of the daughters in Ealing's very successful comedy Here Come the Huggetts, then in 1949 as Molly Reed in the Ealing Comedy Passport to Pimlico.
The film historians Steve Chibnall and Brian McFarlane praise her "quite unusual intensity and a real capacity for depicting working-class lives", and note of her extensive B movie career in the 1950s: "Virtually everything she did is worth watching, for her if sometimes for little else." They add that each of her films "benefits from the instinctive humanity, the sense of her characters' having a past and a place in the world, which she brings to them".
Hylton's first television appearance was in the starring role of Queen Guinevere in the 1956 series The Adventures of Sir Lancelot and from the early 1960s she spent her career entirely in television, where she featured in a number of one-off productions for BBC and ITV drama strands as well as appearing in series such as Dixon of Dock Green, Journey to the Unknown, The Troubleshooters and Take Three Girls. Her most identifiable TV role was Beryl Fisher, the mother of the hapless Betty Spencer (Michele Dotrice) in the BBC comedy series Some Mothers Do 'Ave 'Em.
Hylton's first marriage to film Producer Euan Lloyd ended in divorce, although the couple remained on good terms. The marriage produced a daughter, Rosalind Lloyd, who also became an actress; Hylton and her daughter both appeared in Lloyd's big budget 1978 mercenary drama The Wild Geese, which was Hylton's first screen role for 17 years and turned out to be the last of her career.
Hylton's second marriage to actor Peter Dyneley, whom she met on the set of The Manster, lasted until Dyneley's death from cancer in 1977. Hylton, who had been diagnosed with a congenital heart defect in her late 30s, died of a heart attack in Glasgow on 28 February 1979, aged 52.
