Fur trader. Born in Glasgow, and educated at the University of Glasgow, McGill emigrated for Canada (1765) and travelled the wilderness of central Canada making his money in the fur trade. By 1775, he had established himself as a successful merchant, trading in furs, ammunition and general goods. He was soon a wealthy man.
For many years he served as a city magistrate in Montreal and he was a founder of the Royal Institute for the Advancement of Learning, which set about creating a formal system of educational in Lower Canada. He was also a volunteer Colonel in the Montreal militia and led the defence of the city against the Americans in 1812.
He left £10,000 and one of his estates to found McGill University in Montreal (1821).