MacEwan was born in Brandon, Manitoba, and lived there until the age of thirteen. Because of problems with his father's fire-extinguisher business, the family moved to Melfort, Saskatchewan, to begin a life of farming. As a boy, MacEwan was entrepreneurial, entering into many different businesses, especially cattle. Most of his first big investments were in cows, either for entering into shows or for producing calves and milk. MacEwan also delivered newspapers and sold vegetables and various other items. At the age of twelve, he began working at a grocery store. He went to school and spent most of his time helping out on the family farm.
