William Craig was born either in Edinburgh or Aberdeen. He emigrated to Canada in 1834, when he was 24 and unmarried. He settled first in Sorel, Quebec, and then opened one of the first general stores in Bytown (Ottawa). In 1837, William expanded as a lumber and supply merchant at Sandpoint, then moved across the river to Bristol, Quebec. He included farming in his itinerary, and owned about 3000 acres of arable land. He had a race course, and owned race horses. He is buried in Bristol, Quebec.

Janet McClymont MacJanet married William Craig in 1837. Her father (Thomas MacJanet from Belawearie, Fifeshire) was one of the five original settlers in Bristol, as he immigrated to Canada in 1829. Her sister Mary had married Daniel Cowley (the Cowleys are mentioned in William Craig's will.)

Margaret Campbell Lang, who established these biographical facts, noted that it was rumoured that William Craig had a brother who was in the Black Hole of Calcutta, during the Indian Mutiny.

William and Janet Craig had 12 children, all born in Bristol: