Scholarship on the interpretation of Ireland’s patron saint in the nineteenth century has focused exclusively on Catholic or Church of Ireland historians. However, from the 1830s onwards, Presbyterian writers grappled with Ireland’s patron saint and in so doing used Patrick as a means of contributing to debates about historical scholarship, missionary activity, and identity politics. Presbyterians were relaxed in their reading of Patrick but were also keen to demonstrate that their Patrick was different to those offered by other denominations. Following the great Church of Ireland scholar of the seventeenth century, Archbishop James Ussher, they were keen to reject Catholic claims that Patrick had a papal commission and the popular devotions that surrounded sainthood, asserting Patrick’s independence from Rome and his essentially evangelical doctrine, and rejecting the notion that he had been a diocesan bishop. By ‘proving’ that evangelicalism was the true descendant of the early Irish Church, this ‘Protestant’ Patrick was essential to the effort to convert Catholic Ireland. Patrick thus raises important issues about what mattered to Irish Presbyterians in the nineteenth century. It also offers a means of assessing the multiple identities of Presbyterians and especially the balance between their origins in seventeenth-century Scottish immigration and their Irish identity.