Hill attended school in Durham and then went to Le Manoir in Lausanne, on the shores of Lake Geneva, Switzerland. She obtained a BA at Durham University, and there met her husband, a clergyman. They moved to the remote parish of Matfen, Northumberland, where she played the organ in church and ran a Sunday school.

Hill's career as an author began when her daughter Vicki, then about ten years old, found a story her mother had written as a child and asked for about its characters. The result was a series of eight books about Marjorie & Co, illustrating them herself. These began to be published in London in 1948. They were followed by the Patience series and several others.

When Vicki left home to be a ballet student at Sadler's Wells in London, Hill missed her and began to write her Dream of Sadler's Wells series. She eventually wrote a total of 40 children's books, as well as La Sylphide, a commissioned biography of the dancer Marie Taglioni, and two romances for adults, published in 1978. Hill was then obliged to stop writing by ill health. She is said to have been firm with publishers and to have earned more from her books than many of her contemporaries. Translations of some titles into several other languages appeared, including less usual ones such as Finnish (by Pirkko Biström, 1991), Indonesian (1994), Czech (1995) and Slovenian (by Bernarda Petelinšek, 1996).

More information at Wikipedia.