Scott was born on 14 December 1938 in Morecambe, Lancashire, England. She is the daughter of actors Jimmy Scott and Thora Hird and began her acting career as a child actress known as Janette Scott. Scott was briefly (along with Jennifer Gay) one of the so-called "Children's Announcers" providing continuity links for the BBC's children's TV programmes from the Lime Grove Studios in the early 1950s.
She became a popular leading lady; one of her better known roles as April Smith in the film School for Scoundrels (1960), based on the "one-upmanship" books by Stephen Potter, in which Ian Carmichael and Terry-Thomas competed for her attention. Some scenes for School for Scoundrels were shot at a private members club before its current incarnation as a hotel. The hotel hosted a screening in 2016 with Janette Scott attending and answering questions about filming School for Scoundrels.
Scott's highest profile as a leading lady in British films was from the late 1950s to the mid-1960s, having over a dozen leading roles during this period. She was the female lead opposite some major stars of the time, including Terry-Thomas, Ian Carmichael, Ronald Lewis, Ian Hendry and George Chakiris. She proved adept in a wide variety of genres, including comedy, romantic drama, sci-fi thriller, and period adventure. She gave up her career upon marrying second husband Mel Tormé.
She is best known to American audiences for her role as the parson's wife in the film The Devil's Disciple (1959), starring Burt Lancaster, Kirk Douglas and Laurence Olivier.
She is referenced by name in the song "Science Fiction/Double Feature", the opening number from The Rocky Horror Show and its film version The Rocky Horror Picture Show (performed over the opening credits), for her participation in the 1962 film The Day of the Triffids.
Scott wrote her autobiography Act One at the age of 14.
