He was born in Kirkmichael, Scotland in 1743 and came to Quebec shortly after 1759, and became involved in the fur trade in the regions near Michilimackinac, Lake Superior and Lake Nipigon. Grant became partners with Gabriel Cotté and Alexander Shaw. In 1791, he formed Grant, Campion and Company with Étienne-Charles Campion and Samuel Gerrard; the firm played an important role in the development of the fur trade in the region, becoming share-holders in the North West Company and coming to an agreement with that company regarding access to trading territories.
Born in Kirkmichael, Scotland in 1743, he moved to Quebec around 1759 and became involved in the fur trade near Michilimackinac, Lake Superior, and Lake Nipigon. Grant partnered with Gabriel Cotté and Alexander Shaw. In 1791, he co-founded Grant, Campion and Company with Étienne-Charles Campion and Samuel Gerrard; this firm was crucial in the fur trade region, becoming shareholders in the North West Company and reaching an agreement with that company regarding trading territories.