Ferguson appears to have entered the Scots brigade in the pay of Holland, probably as a gentleman volunteer, some time during the reign of Charles II.

The fight at Killiecrankie, where he is said to have been taken prisoner, left him a regimental major; and in March 1690 he was despatched by General Mackay, who described him as 'a resolute, well-affected officer,’ in whose discretion and diligence he had full reliance, at the head of six hundred men, to reduce the western isles, a service he accomplished satisfactorily with the aid of the Glasgow authorities and the co-operation of Captain Pottinger of the Dartmouth frigate (Ferguson, pp. 15–16).

A few days after, on 1 August 1692, he was appointed lieutenant-colonel of Monro's (late Angus's, now the 1st Cameronians, Scottish rifles), which at the time was in Dutch pay.

Owing to the reductions after the peace of Ryswick the regiment was retained in the Netherlands,[note 1] but in December 1700 it was finally transferred to the British service, and was brought to Scotland.

Ferguson had meanwhile married and been left a widower, and had acquired the estates of Balmakelly and Kirtonhill, on the Kincardineshire bank of the North Esk.

In the campaign of the year following he had a brigade at the forcing of the enemy's lines in Brabant, and afterwards commanded, with the rank of major-general, at 's-Hertogenbosch, where he died very suddenly—the family tradition says by poison—on 22 Oct. 1705.

The General's will had been drawn up by his nephew James Ferguson and as executor he sold the estates of Balmakelly and Kirtonhill and bought those of Kinmundy and Coynach,[1] (now part of the settlement of Clola), Aberdeenshire (Burke, Landed Gentry, 1886, vol.