He was a Highland soldier who after the Seven Years' War received extensive land grants at Albany, New York, becoming a prominent Tory and merchant associated with Simon McTavish and the fur trade.

Having gained a reputation for no-nonsense, he was made a magistrate and given further land at Vermont to bring Ethan Allen and the Green Mountain Boys to order.

As a sergeant-major of the 48th (Northamptonshire) Regiment of Foot, John came to North America in 1756, seeing active service in the Seven Years' War at the Battles of Louisburg and Quebec.

Following the war, he was disbanded and received extensive land grants for his military service east of the Hudson River at Schenectady, Albany County, New York.

He became a merchant and rapidly prospered in business, particularly in the fur trade, becoming a close lifelong friend of Simon McTavish, who sponsored one of his sons.

As one of a handful of Tories in the region he continued to farm, operating mills, a pottery, an ashery and a nail factory, but was ostensibly placed there to bring Ethan Allen and the Green Mountain Boys to order over the disputed the New Hampshire Grants.

He was the first Loyalist to offer his services to Colonel Allan Maclean of Torloisk and his newly formed 84th Regiment of Foot (Royal Highland Emigrants).

His wife and their seven children also made their escape to Canada, first settling at Montreal and then L'Assomption, Quebec, while Munro was deployed in active service over the border.

In 1783, at Sir Frederick Haldimand's request, he undertook a tour of exploration from Quebec City to Halifax via the Témiscouata route on behalf of a group of Loyalists who had obtained land in Nova Scotia.

He was appointed an original member of the Legislative Council of Upper Canada on 12 July 1792, and in December of that year he became a Justice of the District Court of Common Pleas.

Three of their sons served under him during the American Revolutionary War and afterwards became involved with the North West Company, under the auspices of family friend, Isaac Todd.