O'Reilly was the younger son of the Reverend Thomas O'Reilly, an Anglican clergyman from an old Irish family of Westmeath, and his second wife, Rosa nee Smith. He was educated at Sydney Grammar School and in 1879 visited Britain with his family. After his father's death in 1881, O'Reilly's mother opened a preparatory school for boys near Parramatta; Dowell O'Reilly provided teaching assistance.
Although he matriculated, O'Reilly spent only a short time at university. His first employment was as a school teacher in the New South Wales Department of Public Instruction. An enthusiastic cricketer and an officer in the Parramatta Volunteer Rifles, O'Reilly married Eleanor Grace McCulloch on 20 December 1895. Elected to the Legislative Assembly for Parramatta in 1894 as a free trade supporter of Sir George Reid (q.v.), O'Reilly carried the first motion in favour of women's suffrage in 1895. He was a friend of Rose Scott (q.v.) and a prominent advocate for the cause (although he later became disenchanted with it).
On losing his seat in 1898, O'Reilly became a master at Sydney Grammar School until 1909; a second attempt to enter Parliament in 1910 on behalf of the Labor Party failed and O'Reilly joined the Commonwealth Treasury's Land Taxation Department in Sydney. After his wife's death in 1914 he married an English cousin, Marie Rose Beatrice Miles, whom he had met in England in 1879. O'Reilly was survived by a daughter, Eleanor, and two sons from his first marriage. As Eleanor Dark (q.v.) the daughter became a well known novelist.
O'Reilly's literary career had begun in 1884 with occasional contributions to the Sydney Bulletin and other journals. He published Australian Poems in 1885, followed by Pedlar's Pack (1888) which included verse and prose. His selected prose, Tears and Triumphs (1913) and Fivercorners (1920) were reprinted with a selection from his poetry titled Illusions.
O'Reilly was an active member of the Sydney literary scene and friends with John Le Gay Brereton, Christopher BrennanX%2c), Mary Gilmorexl), Henry Lawson, Lionel Lindsay and A. G. Stephens (qq.v.). In 1899 he collaborated with R. F. Irvine (q.v.), Brereton and Brennan in the short-lived Australian Magazine. O'Reilly was his own harshest critic and published far less than he might have hoped. In his own words, 'I cannot recall any period of my life that was not marred by unrest...and every time Fate uprooted me I left something of my life behind - like any other plant' (qtd in Barker, The Emotional Life : Literature and Art :109). E. Morris Miller in his Australian Literature from Its Beginnings to 1935 asserts that 'In Fivecorners O'Reilly is at his best. His stories are finished cameos of the light and shade of human passion; the pulse of life beats in them. The brevity of the stories is commensurate with the brevity of the sentences. Description, conversation, analysis and comment are undetachably compacted into form and suffused with an air of whimsicality.' (41).
(Source: Uther Barker, The Emotional Life : Literature and Art (1968); Frank Bongiorno, '"Every Woman a Mother": Radical Intellectuals, Sex Reform and the "Woman Question" in Australia, 1890-1918', Hecate 27.1 (May 2001): 44-64; Michael Sharkey, 'O'Reilly, Dowell Philip (1865 - 1923)', Australian Dictionary of Biography, Volume 11, MUP, 1988, pp 93-94, Colin Roderick, Australian Round-up: Stories 1790 to 1950, 1953, pp. 359-360.)
