John David Hennessey was the son of John, a cabinet maker, and Eliza Hennessey (nee Shuttleworth). His parents migrated to Queensland in 1860, leaving Hennessey with relatives. In 1872 he entered the Wesleyan College, Richmond to study for the Methodist ministry. He left England for Queensland, keeping a diary of his voyage on the Lammermuir. Fryer Library, Queensland, has a photocopy of the 'Diary of David John Hennessey during His Voyage to Australia, January Eighteen Seventy-Five', a colourful, dramatic narrative.
Hennessey started work as a minister in Stanthorpe in May 1875, where he met James Brunton Stephens (q.v.). Stephens, whom Miller described as a 'poet-schoolmaster', frequently attended Hennessey's services (Australian Literature From Its Beginnings to 1935, p.470). Hennessey left Stanthorpe in 1877 to his second charge at Tenterfield. He married Harriet Butcher in May 1878. After a few more years in the ministry, working in Toowoomba and Brisbane, Hennessey retired from the Methodist Church and joined the Congregational ministry. He continued to preach in various Brisbane churches although 1884 marked his turning to journalism. He had already started a monthly paper, The Christian Messenger, that became a weekly issue and, when a branch office was opened in Sydney, was renamed The Intercolonial Christian Messenger . In 1886 the name was changed to The Australian Christian World edited by Hennessey from 1886 to 1891. He thus played an important part in establishing a religious press in Australia.
Hennessey's wife had died in 1886 and he remarried in 1891. After he sold his interest in The Australian Christian World, Hennessey took his family to Wynnum to attempt growing pineapples. Three of his novels, The Dis-Honourable, An Australian Bush Track and Wynnum all show evidence of having been written in the Wynnum-Redland Bay district. In 1894 Hennessey established an agricultural newspaper, The Australian Field, and in 1896 he issued The New Chum Farmer with Hundreds of Practical Hints on Agriculture and Dairying. His firm of Hennessey and Harper published some of his novels and advertised itself as publisher, printer and author's agent. He wrote and worked for Edmund Barton and the Federalist, an association which may have led to his appointment as secretary to the Royal Reception Committee and secretary to the Commonwealth Celebrations Committee at the time of federation.
The new century marked Hennessey's departure to Victoria, where he used the name David Hennessey for literary purposes instead of J.D. Hennessey or John D. Hennessey. He was publishing short stories and serials in Australian and English magazines. The Sea-Cliff Towers Mystery, published in twenty-nine chapters in Good Luck: An Australian Christmas Annual (1898), was republished in 1915 as The Caves of Shend by Hodder and Stoughton. The Oxford Companion to Australian Literature describes his novels as being 'characterised by graphic descriptions of the Australian scene, both contemporary and past; sensational, melodramatic plots; and romatically happy conclusions'.
In Victoria Hennessey assumed a double career as author and minister. He bought Twickenham House in Richmond where he edited a Victorian church paper, continued his journalistic writing and wrote The Outlaw, a novel that won four hundred pounds in Hodder and Stoughton's novel competition in 1913. In 1927 Twickenham House was sold and Hennessey and his wife went to live at Dromana on the Mornington Peninsula. Hennessey died there after what one obituary described as 'a varied career'.
