He played for the bronze-medal-winning Canadian men's hockey team at the 1968 Winter Olympics in Grenoble, France.

Hargreaves played his minor hockey in Foam Lake, Saskatchewan, where he suited up for the senior Foam Lake Flyers.

He also played junior hockey for the Melville Millionaires, and professionally for the Winnipeg Jets of the WHA.

He finished his career in Nelson, British Columbia, where he played and coached the Nelson Maple Leafs of the Western International Hockey League.

He taught high school and was instrumental in developing hockey programs in Nelson.