In 1525, he was one of a number of lords selected to attend personally on the King and in June 1535 he was appointed an ambassador to France in connection with the King's marriage.
Montrose supported the King in his struggles with the pro-English faction led by Archibald Douglas, 6th Earl of Angus and was rewarded on 29 May 1542 with a grant in feu of the King's lands of Rathernes and Blacksaugh, in Strathearn.