Flora Louise Shaw was born on 19 December 1852 in Woolwich, the daughter of Captain George Shaw (1822-1892), an officer of the Royal Artillery and Marie Adrienne Josephine (née Desfontaines) (1826-1871) of Mauritius. The fourth of fourteen children, the family consisted of four brothers and nine sisters, the first and last of whom died in infancy. On the paternal side of her family, her grandfather, Sir Frederick Shaw (1799-1876) of Dublin, was a member of parliament from 1830-1848, and widely regarded as the leader of the Irish Conservatives. Although Flora and the rest of her siblings were baptised as Roman Catholics in accordance with their mother's faith, they were raised in their father's Anglo-Irish Protestant tradition. These beliefs were challenged as Flora underwent a crisis of faith in the course of her mother's final illness, during which she maintained a close correspondence with Father Lloyd Coghlan, a Catholic priest.

Flora received no formal education during her childhood, although she spent time reading in the library of the Royal Military Academy and at seventeen, having been introduced to and mentored by Oxford professor John Ruskin, was exposed to such figures as Thomas Carlyle and George Meredith and kept up a correspondence with the latter for nearly two decades. After her mother's death and her father's second marriage, Flora left home at the age of twenty and travelled to France to stay with her mother's relatives, in the process becoming fluent in French. Later travelling to her paternal relatives in Ireland, she stayed for a number of years as governess and housekeeper in the home of Colonel Brackenbury, a cousin by marriage, and kept in close contact with the family for the remainder of her life. This period strengthened Flora's notion of her Irish heritage, present in her later children's books and concerns with the Irish issue of Home Rule.

Her literary success began with her children's book, Castle Blair (1877), which was well received and reprinted, followed by the two novels, Hector and Phyllis Browne, both serialized in Aunt Judy's Magazine, the former from 1880-1881 and the latter from 1882-1883. These were followed by A Sea Change (1885), and her first novel for adults, the unsuccessful Colonel Cheswick's Campaign (1886), marking the end of her career in fiction.

In 1883 Flora rented a room in Little Parkhurst near Abinger Common, Surrey, which remained her cottage retreat and later expanded home for the remainder of her life. On the advice of George Meredith she took up journalism and, under the guidance of W. T. Stead of the Pall Mall Gazette, began her career as a political journalist, kickstarted by her article on political prisoner, Zobehr Pasha, published on 28 June 1887. After serving as a correspondent in Eygpt for the Pall Mall Gazette and the Manchester Guardian from 1888-9, she returned to London to write freelance and was offered a job by C. F. Moberly Bell, the assistant manager of The Times, who had met her in Egypt.

After a bout of influenza, Flora travelled to South Africa in a dual effort to recover and report, investigating the colony's prospects in mining, agriculture, industry and social welfare. In light of these successes, The Times sent her on a circumnavigatory trip to report from Australia and New Zealand, which she did from 1892 to 1893. Her return in July brought her the position of colonial editor of The Times, enabling her to settle with three of her younger sisters at 130 Cambridge Street, London. She had a close relationship with her sister Louise (more commonly referred to in their letters as "Lulu" or "Lulie") who managed her finances and acted as her link to Britain when she was travelling on business. Reporting widely on imperial issues, Flora was caught up in the political controversy surrounding the Jameson Raid into the Transvaal on 29 December 1895. She was required to testify before the House of Commons Select Committee on British South Africa due to her exchange of incriminating telegrams with Cecil Rhodes. During this time she corresponded frequently with those imprisoned or incriminated by the Raid, including Leander Starr Jameson, Colonel Francis Rhodes, and the Colonial Secretary, Joseph Chamberlain. Exonerated from all charges, she travelled to Canada in 1898 to report on the Klondyke Gold Rush, exposing the conditions of the minings camps and towns and the network of official corruption in the Yukon Territory. Flora returned to report on the South African War and finally resigned from The Times in September 1900.

Following romantic attachments to Colonel Charles Brackenbury and Sir George Goldie, Flora married Sir Frederick John Lugard (1858-1945), high commissioner of Northern Nigeria, in Madeira on 11 June 1902. After some time at Government House in Nigeria with her new husband, her health required her to return to England where she gave lectures and worked on numerous historical narratives of Britain's colonies, including A Tropical Dependency (1905). All of her works affirmed the essential importance and value of Britain's imperial role. She accompanied Lord Lugard when he was appointed governor of Hong Kong in 1907, returning to Britain in 1912 due to her health. She remained engaged in political activities, corresponding with MPs and legislators over subjects such as Irish Home Rule, refugees, food supply during World War I and issues of labour worldwide. She died at Little Parkhurst on 25 January 1929 after an extended illness.

Biographical history compiled with reference to Flora Shaw's entry in the Oxford Dictionary of National Biography written by Dorothy O. Helly and Helen Callaway.