The papal bull confirming the erection of this new prebend did not come however until 5 May that year, shortly before Dúghall became bishop of the neighbouring diocese of Dunblane. This letter stated that Dúghall "also holds a canonry and prebend in the diocese of Dunkeld". Dúghall can be found holding a canonry and prebend in the diocese of Dunblane as early as 23 November 1375, a prebend he held in plurality with Kilmore in Argyll. On 11 March 1380 he was provided to yet another benefice in the diocese of St Andrews, and then to another prebend and canonry in the diocese of Dunblane. By 1380, he was the secretary and chaplain of Robert Stewart, Earl of Fife (later Duke of Albany), son of King Robert II of Scotland. At Avignon on 2 June 1380, he presented a roll of petitions on the Fife's behalf to the pope. On 12 September, while still at Avignon, he was provided by Pope Clement VII to the bishopric of Dunblane; this provision apparently followed an earlier election. He had almost certainly received consecration by 11 October but his consecration had certainly occurred by 13 February 1381. On the latter date he was back in the Kingdom of Scotland, witnessing a charter of David Stewart, Earl of Strathearn, brother of the earl of Fife. Thereafter notice of Bishop Dúghall in the surviving sources is limited. He is next found on 1 October 1392 witnessing two charters of Euphemia I, Countess of Ross at Stirling, the royal burgh on the edges of Menteith and the diocese of Dunblane. A papal mandate of 27 October 1394 provided one Dómhnall "de Bute" as Dean of Dunblane, annulling Bishop Dúghall's own provision of Dómhnall made "in ignorance of the reservation" earlier made by the pope. On 4 September 1395 the bishop is mentioned in a papal document concerning the succession to one of the churches in his diocese. In 1396, it is known that he travelled to Avignon once again; a roll of petitions presented by Dúghall on behalf of 20 Scottish people and 3 continental Europeans was granted by Pope Benedict XIII on 1 August 1396. The last ever notice of Dúghall occurs in a charter of the lord of Byres, wherein Dúghall appears along with the Duke of Albany and Walter Trail, Bishop of St Andrews; the charter can be dated between 1398 (creation of the Duchy of Albany) and 1401 (the death of Walter Trail).