On 27 January 1561 he received letters of denization from the Crown. Becoming an important adviser, he was made dean of Christ Church Cathedral, Dublin, in 1565, and a member of the Irish privy council. In 1585 he was promoted to the bishopric of Kilmore, on the recommendation of Sir John Perrot, Lord Deputy of Ireland, and was allowed to hold in commendam his deanery and archdeaconry. From Kilmore he was translated in May 1589 to the archbishopric of Armagh, still retaining his minor preferments; in recognition of service the payment of his first fruits was remitted.. In 1591, in answer to a circular appeal from Sir William FitzWilliam, Lord Deputy, he gave towards the building of Trinity College, Dublin. He died in Dublin 2 March 1595, and was buried in Christ Church. He firstly married Margaret, daughter of Christopher Plunket of Dunsoghly in County Meath, and sister of the Right Honourable Sir John Plunket. Their son was Sir Christopher Garvey. His second wife was Rose, widowed daughter of Thomas Ussher, and his successor in the archbishopric was his brother-in-law, Henry Ussher.
A treatise is ascribed to him by Anthony Wood, The Conversion of Philip Corwine, a Franciscan Friar, to the Reformation of the Protestant Religion, an. 1589, published by Robert Ware in his Foxes and Firebrands, Dublin, 1681, from an original found among James Ussher's manuscripts. Corwine was nephew to Hugh Curwen.