In the year of his ordination, he was presented by his uncle to the family living of Bothal, Northumberland, and by the influence of Queen Caroline, appointed to a royal chaplaincy at only 25. In 1739, as heir of his great-grandfather, William Drummond, 1st Viscount Strathallan, who had entailed a portion of his Perthshire estates to form a provision for the second son of the Kinnoull family, he assumed the name and arms of Drummond. As royal chaplain, he gained the confidence and esteem of George II, whom he attended during the German campaign of 1743, and on 7 July of that year preached the thanksgiving sermon for the victory of Dettingen before the king at Hanau. On his return to England he entered on a prebendal stall at Westminster, to which he had been appointed by his royal patron in the preceding April. On 9 June 1745, he was admitted BD and DD at Oxford.