Carola Mary Anima Oman was born on 11 May 1897 in Oxford, the second of three children of the military historian Sir Charles Oman (1860–1946) of All Souls and his wife Mary (1866–1950), daughter of General Robert Maclagan of the Royal Engineers. She described a rather sumptuous and sociable childhood in a final book illustrated with photographs, An Oxford Childhood. As a child she wrote several plays that were performed by friends. Another early interest was photography. She was sent in 1906 to Miss Batty's, later Wychwood School in Oxford. She would have liked to have gone to boarding school, but her parents would not agree, and she continued at Miss Batty's until the spring of 1914.
The family moved in 1908 into Frewin Hall, now part of Brasenose College, Oxford. Her brother Charles (C. C. Oman) became a keeper of the Victoria and Albert Museum and wrote several books on silverware and other domestic metalwork. The set designer Julia Trevelyan Oman (1930–2003) was her niece. She was married on 26 April 1922 to Gerald Foy Ray Lenanton (1896–1952), son of a timber agent, with Hensley Henson officiating, as he had at her christening. The couple remained childless.
The novelist Georgette Heyer was a lifelong friend, who even took the time to compile a 16-page index for Oman's Britain against Napoleon, published in 1942 by Faber and Faber. Another writer friend in Oxford was Joanna Cannan, who dedicated her 1931 novel High Table to Oman.
Oman's war work as a probationary VAD nurse in Oxford, Dorset, London and France contributed to a book of verse, The Menin Road and Other Poems (1919). Verse of hers also appeared in the 1931 edition of The Bookman Treasury of Living Poets, edited by Arthur St. John Adcock. Some of her work in the 1920s and 1930s appeared initially under her married name. Lenanton was knighted in 1946 after serving as director of home timber production in World War II. They settled at Bride Hall, a Jacobean mansion in Ayot St Lawrence, Hertfordshire. In 1965, Oman produced Ayot Rectory – A Family Memoir, about the Sneade family, who had lived in the village from 1780 to 1858. Oman has been quoted as speaking warmly of George Bernard Shaw, a neighbour in the village.
Oman's writing career of more than half a century produced over 30 books of fiction, history and biography for adults and children. She soon began to focus on historical biography. Henrietta Maria (about the French queen, 1609–1669) appeared in 1936, The Winter Queen: Elizabeth of Bohemia in 1938, and her authoritative prize-winning biography of Nelson in 1946. This drew on a wealth of material not available to the previous biographer Alfred Thayer Mahan fifty years before, notably the papers of Lady Nelson assembled by the founder of the Nelson Museum, Monmouth.
Carola Oman's 1953 biography of Peninsular War general Sir John Moore (1953) won the James Tait Black Memorial Prize in that year. The academic standing of the book is clear from the fact that she was called upon on 10 July 1954 to lecture on Moore to the Anglo-American Conference of Historians, held at the Institute of Historical Research, University of London. Other subjects of biographies were David Garrick (1958) and Sir Walter Scott: The Wizard of the North (1973). The warm reviews of the latter include one by the English poet Elizabeth Jennings in the Catholic Herald.
Oman wrote several historical novels for children, of which a story of the Third Crusade, Ferry the Fearless (1936, later a Puffin book), Robin Hood (1937, numerous editions) and Alfred, King of the English (1939, reprinted several times) were the most popular.
Carola Oman was appointed a trustee of the National Maritime Museum and later of the National Portrait Gallery. She was appointed a CBE in 1957. She died at Ayot St Lawrence on 11 June 1978. There is a memorial to her and her husband in the village church.
- The full text of the David Garrick biography online: Retrieved 8 July 2012.
- Carola Oman's WW1 poem "Unloading Ambulance Train" on a school website: Retrieved 1 August 2012.
- Entry for Carola Oman in The Cambridge Guide to Women's Writing in English Retrieved 8 July 2012. Pay-walled.
- London: Hodder and Stoughton, 1976. ISBN 0340212659
- An Oxford Childhood, passim.
- Josephine Ransom: Schools of Tomorrow in England (London: Bell, 1919). Retrieved 8 July 2012.
- ODNB entry by Mark Bostridge. Retrieved 8 July 2012. Pay-walled.
- Orlando project: Retrieved 8 July 2012.
- A detailed account of the history of Frewin Hall: Retrieved 8 July 2012.
- "Society Meetings, 18 June 1958". Folklore 69 (3): 216. 1958. JSTOR 1258870.
- Obituary: Retrieved 8 July 2012.
- The Indexer 17/1 (April 1990). Retrieved 1 August 2012.
- An Oxford Childhood, pp. 119, 133, 143, 149 and 174.
- Bookseller's description Retrieved 1 August 2012.
- An extract from Shaw the Villager... by Allan Chapelow (New York: Macmillan, 1962): Retrieved 8 July 2012.
- All Poetry site. Retrieved 8 July 2012.
- Historical Research 27/76 (November 1954), pp. 214–17.
- British Library records: Retrieved 8 July 2012.
- 6 April 1973. Retrieved 1 August 2012.
- Amazon listings Retrieved 8 July 2012.
-  Better citation needed.