Laurence Hynes Halloran was born on 29 December, 1765, probably at Ratoath, County Meath, Ireland. His father was a West Indian planter, and his mother, Eleanor Hynes, was descended from landed gentry. Orphaned at an early age, Halloran was educated at Christ's Hospital school in London, which he attended from 1774 to 1781. From there Halloran entered the Royal Navy, where he tutored in mathematics and navigation, before being discharged in 1783, following an incident in which he stabbed and fatally wounded a fellow mid-shipman. Acquitted of murder, Halloran then established an academy at Exeter, the later Alphington Academy, which he ran successfully for about a decade. In 1792, during his period at Alphington, Halloran converted from Catholicism to the Church of England, and from about this time he entertained ambitions of entering the ministry. However his efforts to this effect remained unsuccessful, and at one point the Bishop of Exeter refused Halloran's application for ordination due to his radical political views, and his supposed immorality.
Following his insolvency in 1796, Halloran left Alphington. He then embarked on a remarkable 22 year career in which he masqueraded as a Church of England clergyman. During this period he re-entered the navy as a chaplain (he was on H.M.S. Britannia at the Battle of Trafalgar in 1805), and served as Chaplain of Brigade at the Cape of Good Hope, from where he was eventually banished after a bitter personal dispute with the colony's governor. Returning to England in 1811, Halloran continued to pose as a clergyman by forging his credentials and adopting assumed names. Even the Doctorate in Divinity which he gained from King's College, Aberdeen, was obtained by deceit. Halloran finally came undone by forging a frank on a letter, for which he was transported to New South Wales for seven years.
Soon after his arrival in Sydney, Halloran was granted a ticket-of-leave by Governor Macquarie, and in 1820 he opened a school. In 1824, following the death of his second wife Anna, he married Elizabeth Turnbull, then 17 years old. In 1825 he was appointed founding headmaster of the Sydney Free Public Grammar School, but almost immediately came into conflict with the trustees, which was probably a reason behind their decision to temporarily wind up the school the following year. In 1827 Halloran began his weekly newspaper, the Gleaner, however his intemperate personality and lack of experience ill equipped him for the venture, and it folded after only four months. From this point on, Halloran's position was dire. He had a large family to support, and he was burdened by debt, which in part resulted from a libel action brought against him as editor of the Gleaner. In 1828, out of pity, Governor Darling appointed him to the position of Coroner, but had to dismiss him a short time later when he came into conflict with Archdeacon Thomas Scott.
In May 1830, Halloran made another attempt at journal publication. He proposed a 'Weekly Miscellany' from which would be excluded all political comment and which would concentrate on 'moral, philosophical and literary' themes. Halloran cited the care of his 'numerous household' as the reason behind his 'renewed exertions in the Field of Literature' and requested prospective subscribers to leave payment with the printer Arthur Hill (q.v.). (Sydney Monitor, 5.268 (1 May 1830):1) It appears the 'Miscellany' was never published.
Notably, Halloran is listed in Watkins and Shoberl's Biographical Dictionary of the Living Authors of Great Britain and Ireland (1816).