She was born at Old Bawn, near Tallaght, County Dublin, the daughter of John Furlong, a sporting journalist.
[2] In 1899, Furlong published Roses and Rue, favourably reviewed by Stopford Brooke and others, and in 1907 Tales of Fairy Folk and Queens and Heroes.
[2] She contributed to several journals, including the Irish Monthly, the Weekly Freeman, Chambers's Journal, and the nationalist Shan Van Vocht, run by Alice Milligan, and Anna Johnston (Ethna Carbery).
[4] In 1900 she was a founder-member of Inghinidhe na hÉireann, the revolutionary women's organisation led by Maud Gonne.
Furlong was elected a vice-president of the association, along with Jenny Wyse Power, Annie Egan and Anna Johnston.