Elsie Rosemary Laurence was born in 1928 in Hutton, Essex in England and moved with her family to London in 1933. She was evacuated in 1940 during The Blitz to stay with relatives in Devonshire, where she contracted tuberculosis and peritonitis. It was while she was convalescing that she decided on a career in medicine, entering the all-woman Royal Free Medical School in London in 1945. In 1950 she married Roger Rue, a pilot instructor of Belgian descent in the Royal Air Force. When she told the medical school dean that she was changing her name, she was told that she could not stay at the school if she was married. She was instead accepted at the University of Oxford, qualifying in 1951 after taking the University of London exams. Her first job was at an extended-care hospital in Oxford. She did not tell her employers that she had a husband or a newborn son, as many hospitals then didn't employ married women. She was eventually sacked when her employers learned she was married with children. In 1954, she contracted polio from a patient, becoming the last person in Oxford to get it. Polio gave her the major, lifelong disability of having one bad leg. This left her unable to walk, even with crutches, or perform basic tasks such as carrying a medical bag. She spent time teaching at girls' schools. Unable to walk up front steps for interviews, she had to turn down several medical jobs. New hospitals were constructed in Swindon, Reading and Milton Keynes, with basic modules that could be incorporated into every hospital. In 1960, she was named Assistant County Medical Officer for Hertfordshire and worked as a part-time paediatrician in Watford. She spent an academic term at the Institute of Child Health in London. In 1965, she was offered the job of Senior Assistant Medical Officer for the Oxford region, running that region's health authority. In the early 1960s new money was allocated by the government to rebuild the crumbling medical system in the UK. Dr Rue ensured that Oxford got a fair share.
In her last few years, Dame Rosemary continued to take an active interest in health service matters, despite both breast and colon cancer. She died, aged 76, at her cottage in Stanton St John, Oxfordshire on Christmas Eve 2004, aged 76. She was survived by her two sons.