Janet Ann Moore was born on 5 February 1880 at Hanley Castle, Worcestershire, England, to Frederick Morris Moore, a carpenter, and his wife, Agnes Thompson Muir. Janet's father drowned in 1881 and in 1889 her mother brought her and her three brothers to New Zealand. The travellers experienced an eventful voyage aboard the Ruapehu: a severe storm in the Bay of Biscay created havoc, and when the ship reached the tropics a dog bit Janet, leaving her arm scarred for life.
The family settled in Dunedin where Agnes Moore's sister lived. Janet commenced her nursing training at Dunedin Hospital in 1904, where her duties included scrubbing the floors of the wards at night. After registering as a nurse in 1907 she completed her midwifery training at the Forth Street Maternity Hospital. For the following 10 years she was a member of the staff of the Dunedin Hospital as sister in charge of a variety of wards and as a nursing supervisor.
Janet Moore joined the New Zealand Army Nursing Service in March 1915. She later recalled the drab uniforms and grey bonnets, commenting that 'I heard these hats called the anti-matrimonial hats!' She left New Zealand in April 1915 with the first contingent of the nursing service. From June she worked at a military hospital in Egypt. The sheer number of sick and wounded soldiers put severe demands on the supply of medical and nursing transport services, and Moore's next appointment was to a hospital ship transferring soldiers from the front line to general hospitals in Cairo.
The New Zealand government had begun setting up hospitals in England in mid 1915, and in June the following year Moore transferred to Balmer Lawn Hospital, an old English hotel converted to a section of No 1 New Zealand General Hospital at Brockenhurst. The Somme offensive of 1916 brought large numbers of wounded and sick. By September the hospital was 'standing on its head – operations galore and [nurses] scarcely knowing what to do first'. Convoys of casualties came every day and at times the work became so heavy that Canadian and Australian nurses were called in to assist. In July 1916 one nurse recorded 'Dressings by the thousand, and some of them are simply appalling'. Many soldiers had septic wounds and nurses recalled the 'horrific' reek of gangrene throughout the wards. Balmer Lawn became the first place to use bismuth iodoform for wound dressings, and one nurse described it as 'one of the most wonderful war-time treatments', which relieved soldiers of many painful dressings. The hospitalised soldiers or 'Blue Boys', so named because of their blue hospital attire, and nurses working at Balmer Lawn appreciated Moore's efficiency. She was made an associate of the Royal Red Cross as public acknowledgement of her war work.
Following the armistice in November 1918 Balmer Lawn and the other British-based New Zealand hospitals wound down, and by February 1919 Moore's military nursing career had been terminated. After her return to New Zealand she spent some months teaching home nursing under the auspices of the Department of Public Health and for a short time nursed at a private neurological hospital in Dunedin. Between 1921 and 1924 she was matron of Waikato Hospital, Hamilton. It was noted for its poor history of passes in the state nursing examination, and in response to her enthusiastic reorganisation of the standard of nursing a local newspaper headline advised 'Steady on it, Janet'. She also shook up the gardening section, requiring the gardeners to wear a uniform.
Janet Moore next took up a position with the Department of Health and in 1924 was sent to London to study hospital administration at Bedford College for Women. This was intended to prepare her for a position as lecturer for the new diploma of nursing at the University of Otago. Her studies covered teaching methods and new ideas on nursing administration, and she gained valuable experience during 18 months in Europe and America. Moore spent her sea voyage to England aboard the Remuera assisting with nursing duties. These involved some members of the 1924 All Black team, one of whom had crawled out a porthole and broken his arm. In recognition of her nursing service for the team Moore received a gold travelling clock.
Returning to New Zealand in 1925, Moore found that a disagreement over responsiblity for the payment of salaries meant that there was no funding for the diploma of nursing; three students who had already enrolled had their studies redirected to home economics. Instead, Moore spent the next three years carrying out duties ranging from classroom teaching to advising the government on nursing education. As a member of the Department of Health she deputised for the director, Division of Nursing, preparing reports and overseeing the standards of nursing and midwifery education.
In 1928 the Department of Health began a postgraduate course for trained nurses at Victoria University College. Mary Lambie and Janet Moore organised the collaboration between the two institutions, and set in place the syllabus of studies for future leaders in nursing administration and education and community health work. For the next 12 years Moore and Lambie led the movement for post-registration nursing education.
Janet Moore retired in 1940, one year after being appointed an MBE for services to nursing. During the Second World War she took up an appointment as matron of a casualty clearing station for sick and wounded soldiers. Janet Moore never married. She died at Silverstream Hospital near Wellington on 11 January 1968 after a long period of ill health. She had contributed significantly to the professionalisation of nursing education in New Zealand.