Her father was made bankrupt in the year Nancy was born and he died in 1867, forcing a family move to the village of St Georges, now a parish of Telford.

[1] Bailey initially had plans to become a writer, but for financial reasons she had to take various other jobs, eventually working at the College of Arms in London where she prepared abstracts of wills.

On 15 October 1892, a notice in The Englishwoman's Review advertised that Miss Bailey had opened an office in Bedford Square, London, to "undertake all kinds of indexing".

[3] She received employment references on her indexing from the prime minister's office,[3] the librarian of the House of Commons, and Richard Garnett, Keeper of Printed Books at the British Museum.

She obtained a post with the Pearson's Weekly tabloid magazine as its indexer and soon needed to hire assistants to help with the office workload.

[1] In 1893, British suffragist and journalist Margaret Bateson interviewed Bailey about indexing for the 'Professional women on their professions' series in Queen magazine.

A letter from newspaper editor W. T. Stead quoted in this 1894 issue congratulated and thanked Bailey for her "noble service" on indexing Hansard.

She was diagnosed with cancer in 1912 and moved to a cottage on the country estate of her friend Arthur Heygate Mackmurdo in Wickham Bishops, Essex.

Stead's words, she was owed thanks "for demonstrating the capacity of woman to do the work" and he acknowledged "that important post you have won for womanhood".