Her writing career began in 1956 when she got a job as a cub reporter on the Middlesex Independent. She then moved to public relations and had a variety of jobs, ending up in book publishing. In 1961 she married publisher Leo Cooper, who comes from Long Preston, whom she had first met in Yorkshire in 1948. They have two children, Felix and Emily, and various cats and dogs. They live in an old house in the Cotswold area of Gloucestershire where they moved in 1982.
In 1998 she received a Lifetime Achievement Award at the British Book Awards. Jilly is now working on a novel about schools. Jilly Cooper's books have sold over 11 million copies in the UK alone. Her books have been translated into Dutch, French, Italian, Spanish, German, Greek, Japanese, Norwegian, Swedish, Polish, Russian, Finnish, Hungarian and Lithuanian as well as being published in The United States.