[4] Although evidence for Fullerton's early career may be doubtful and slight,[5] James VI certainly bought diamond rings for the use of his diplomats, including one for David Foulis in July 1595, "to be employed as we have given direction" as a gift in London.
[6] Known as "a Scotch gentleman of great learning and very great worth", in 1611 Fullerton was proposed for a leading role in the household of Charles I of England (then known as the Duke of York), and summoned from Dublin where he is said to have been involved in the education of James Ussher at Dublin Free School,[7] and was Clerk of the Cheque of the Army in Ireland,[8] and in 1610 a commissioner at the conference of deputies for the Plantation of Ulster.
[9] Prince Henry supported his appointment, but the role was given to Robert Carey after the Earl of Suffolk spoke to the King in his favour.
[10] Fullerton was given other employments, and was a surveyor of Prince Henry's estates, valuing the income from his lands.
Fullerton's signature frequently appears on surviving documents, indicating he regularly attended meetings and was involved in much of council's business.
[18] A royal gift of lands at Gillingham, Dorset, held jointly with a courtier colleague George Kirke, proved troublesome when tenants protested at their enclosures and improvements.