During the Jacobite rising of 1689, he commanded the Earl of Argyll's Regiment of Foot, the primary unit involved in the Massacre, after which he was posted to Flanders for the Nine Years' War, where he remained until the 1697 Treaty of Ryswick.

[1] Little is known of Duncanson's early years, and there is no record of any marriage; the first time he makes an appearance was during Argyll's Rising in 1685, launched in response to the succession of the Catholic James II.

After the Glorious Revolution in 1688, these exiles were used to replace those loyal to James II or appointed to new regiments raised by the Scottish and English Parliaments.

This threat never arose and in July 1690 they moved to Fort William as part of the force commanded by Colonel John Hill, the military governor tasked with pacifying the Highlands.

[7] As instructed by Lord Stair, Secretary of State for Scotland, on 12 February Colonel Hill issued orders to Lt-Colonel Hamilton and Duncanson.

Besieged by the French on 25 July, the garrison commander Ellenberg capitulated two days later; Duncanson protested and refused to sign the terms of surrender.

[14] Duncanson went onto half-pay and spent several years in Debtor's prison, for £1,200 owed to a Joseph Ashley for clothing supplied to the regiment in 1696; this was eventually settled by the Treasury.

Promoted Colonel in February 1705, Duncanson died of wounds sustained leading an assault on the Spanish border town of Valencia de Alcantara on 8 May.