Stewart was born at Slodahill, near Lockerbie, Dumfriesshire, Scotland, to soldier and journalist John Stewart, and his wife Jessie Murray. All of Stewart's siblings were sent to boarding school, but she stayed at home to study under a governess. Later in life she showed regret for missing the opportunity to study abroad like her sisters.
Career
Stewart began working at St Thomas' Hospital in London, England at the age of 23, as a special probationer in the Nightingale Training School for Nurses. After working in the Training School for nine months Stewart rose to become a sister of the surgical ward with 20 beds, Alexandra Ward. The Nightingale training had emphasized the ideas of practical nursing experience over theoretical instructions, and possibly most importantly to Stewart, the moral values that all nurses have to possess to be successful and effective. Stewart left St Thomas' in 1885 when she was chosen to become matron at a smallpox hospital in Darenth, near Kent, England. Despite Stewart's organization and hard work to keep the camp running, it was shut down in 1886. In the summer of 1887, Stewart became the matron of St Bartholomew's Hospital in London. Stewart brought more order and education to the nursing program than the past administration, and enacted a set of skills the nurses had to learn and perfect or they would be dismissed from the program. She created a four years training system for nurses-to-be. After the first year they were required to take an exam on all of the information they had learned, and if they passed if they could become probationers. During the second and third year they received lectures on information relevant to nursing, and the third year they were examined. After the third year they received a certificate, but could not practice until after the fourth year. Stewart published Practical Nursing with Dr H. E. Cuff in Fall of 1899, in an attempt to describe how nurses should work, with reasoning for the treatments carried out. The most emphasized point was the idea that training should be required and that hospitals could create their own training programs and hire nurses straight after. Another volume was published in 1903, and then the second edition was published in 1909. After her death in 1910, the assistant matron of St Bartholomew's continued writing and published a third edition in 1911.
Death
Stewart's health began to deteriorate in the latter portion of 1909. She was last seen in public in the early winter of 1910 at a conference to discuss a Bill. Despite her ill health, Stewart still was a lively speaker at the conference. Stewart died on March 6, 1910 in Chilworth, Surrey in the presence of her dear friend, who was once matron of St Bartholomew's, Ethel Gordon Fenwick.