Gullett was the first resident medical officer at the Crown Street Women's Hospital from 1901 to 1902 and resident surgeon at
Brisbane's Hospital for Sick Children from 1902 to 1903. She was a
GP at
Bathurst from 1906 to 1911, when she returned to
Wahroonga to live with her sister Minnie. The sisters campaigned together for mental health reform, but Lucy's medical practice declined as she had less need for income. During
World War I she travelled to Europe at her own expense to serve the
Red Cross at a military hospital in
Lyon. She was a medical officer in
Sydney during the
influenza epidemic in 1919. From 1918 to 1932 she was an honorary outpatients physician with the Renwick Hospital for Infants, and she was a councillor of the Sydney District Nursing Association from 1934 to 1949. In 1921, Gullett founded the New South Wales Association of Registered Medical Women, serving as secretary. Together with the president, Harriet Biffen, she took a leading role in establishing the New Hospital for Women and Children, which was renamed the
Rachel Forster Hospital for Women and Children in 1925. Gullett opened the Lucy Gullett Convalescent Home in 1946. In 1932 she ran unsuccessfully as an independent women's candidate for the
New South Wales Legislative Assembly, contesting the seat of
North Sydney Gullett was elected to the United Associations of Women executive committee in 1935 and served as vice-president from 1936 to 1938 and in 1943. == Personal life ==