John Owen is one of the most widely read theologians of church history among contemporary evangelicals. He has a reputation as an exemplary producer of orthodox Trinitarian piety and polemical defence of the Reformed catholic faith. Yet he had a complex relationship with creedal Christianity. At times his rejection of creeds and councils were mistaken by his contemporaries for sympathy with Socinians, Quakers, and other groups in the English Revolutions – those who claimed to repristinate the simple faith of the Apostolic church. On other occasions he led the making of national creeds which drew on the theology of Nicaea to outlaw heterodox theological opinion. And in polemical contests with Roman Catholic apologists, he could display how his knowledge extended beyond Trinitarian debate to the potential uses of the ecclesiological pronouncements of the Council. His faith in the power of creeds was not a settled maxim. This paper will examine Owen’s reception of creedal Christianity and of the Nicaea in particular through the texts and contexts in which he variously appealed to and questioned their usefulness. It will remind us that Owen was a flesh-and-blood theologian, who was impacted by the rise and fall of Puritan fortunes and the triumphs and disappointments of his own attempts at confessionalisation and the securing of an orthodox church.