Thursfield was born at Kidderminster in 1840, the son of the physician Thomas N. Thursfield and Sarah Thursfield née Pardoe. He was educated at the Merchant Taylors’ School in London and then Corpus College at Oxford. He remained at Oxford as a college tutor and in other academic roles until 1877. He then joined ‘The Times’ as a leader writer and by about 1880 he had begun to specialize in naval affairs. He represented the newspaper in the naval manoeuvres of 1887 and in every subsequent year when correspondents were admitted. When Alfred T. Mahan's book 'The Influence of Sea Power upon History' appeared in 1890, Thursfield's review was the first that adequately recognized its importance. He was invited by the Admiralty to lecture on the subject of the training of seamen at the Royal United Service Insitution in 1900 and at the invitation of the Staff College, Camberley, on the 'Higher Policy of Defence' in 1902. At this time became closely associated with the reforms of the First Sea Lord Sir John A. Fisher. After the First World War he wrote the four naval volumes of ‘The Times Documentary History of the War’. Thursfield was knighted in 1920. Thursfield married Emily Elizabeth Hannah Herbert in 1880 and the Thursfield family lived at Bloomsbury, Great Berkhamsted, and finally at Golders Green. His son Henry (Harry) George Thursfield became an officer in the Royal Navy. His daughter Dorothea (Dolly) Thursfield later Holland was for seveal years a chief officer of the Girl Guides.
The papers were presented by Sir James Thursfield's son, Rear-Admiral Henry George Thursfield. THU/1-2 were donated in 1947 and consist of letters received by Thursfield, printed papers and proof copies of articles on naval matters, circa 1885-1914. There is a long series of confidential Admiralty and official memoranda sent by Admiral of the Fleet Lord John A. Fisher. There are also printed articles from journals, circa 1908-1910, and reports on the naval manoeuvres in 1894-1901 issued by the Intelligence Department, Admiralty. THU/3-6 were mainly donated in 1962 and comprise letters, ephemera and photographs. Many of the letters from family and friends relate to his son’s naval career from 1897 onwards. There is a small number of letters written by his wife Emily E.H. Thursfield, 1886-1933.