Since 1900, the family sold seed potatoes throughout New Brunswick and exported to Cuba and Latin America.
With the benefit of ensured quality and the ability to export long distances with a value added product, the business started growing.
With Harrison's personal and business skills and the close relationship with his brother Wallace, the McCain Foods business eventually grew to over 55 factories worldwide and the number one french fry company in the world.
Harrison named his nephew, Allison McCain, son of his late brother Andrew, as his successor in 2002.
He was married to Marion "Billie" McCain, daughter of the former premier of New Brunswick John McNair.