Bruce, William (1702–55), publisher and writer, was born in Killyleagh, Co. Down, the youngest of the three sons of the Rev. James Bruce (qv) (1660?–1730), and his wife, Margaret (née Trail), of Tullychin (d. 1706). He was educated at the presbyterian academy in Killyleagh, where he began a lifelong friendship with his cousin the philosopher Francis Hutcheson (qv) (d. 1746). By the mid-1720s Bruce had moved to Dublin, where he became the business partner of John Smith, a bookseller and publisher at the Philosopher's Head in Blind Quay. As Smith and Bruce they published the Irish editions of Hutcheson's works, beginning with An inquiry into the original of our ideas of beauty and virtue (1725), as well as works by Arthur Dobbs (qv) (Essay on trade, 1729), Henry Neville, and James Harrington. Bruce was prominent in Dublin presbyterian circles as an active supporter of the non-subscribers, and he collaborated with his close friend John Abernethy (qv) in writing the influential Reasons for the repeal of the sacramental test (1733; reprinted as Scarce and valuable tracts and sermons, 1757).
In 1738 Bruce retired from bookselling and became tutor to the son of Hugh Henry, a Dublin banker and one-time MP for Antrim. He accompanied his pupil to Cambridge, Oxford, and Glasgow, where he came into contact with the ideas of the Scottish Enlightenment. In 1745 he settled in Dublin, where he was an elder in Wood Street (the congregation of his nephew Samuel Bruce). Despite his radical religious views (he was reputedly an Arian), Bruce was a respected figure in the synod of Ulster, which, in 1750, approved his plan for the Presbyterian Widows' Fund. This scheme, which came into operation the following year, earned a vote of thanks from the synod. Bruce's political outlook was also radical; he supported the campaigns for reform of Charles Lucas (qv) and, alongside friends such as Thomas Drennan (qv), James Arbuckle (qv), and Rev. James Duchal (qv), formed the core of a liberal dissenting group in Dublin. He maintained his literary interests, and two political pamphlets from the 1750s have been ascribed to him: Some facts and observations relative to the fate of the late linen bill (1753) and Remarks on a pamphlet entitled ‘Considerations on the late bill for paying the national debt’ (1754).
Bruce died, unmarried, at his home on Blind Quay on 11 July 1755, and was buried in Hutcheson's tomb in St Mary's graveyard, Dublin. Shortly after his death he was memorialised by his friend Gabriel Cornwall (d. 1779) (An essay on the character of the late William Bruce, 1755) and Smith's publishing firm (Brutus, a monody to the memory of Mr Bruce, 1756). Collections of his papers are held in the NLI and the National Library of Scotland, Edinburgh.