Born in Windsor, Ontario, Canada in 1943, his Father had been posted to Australia briefly by Ford and later encouraged his son to consider emigrating there.

He bought the right to open ten KFC franchises in Western Australia, raised $10,000 from each of thirty people to launch the Business in December 1969, having moved with his wife and young child. Those who invested $10,000 then, had an investment worth around $8.9 million as of March 2006.

Cowin also owns a meat processing Business that exports throughout the world, he sold a substantial investment in Stanbroke Pastoral Company, one of the country's biggest cattle station operators. He is also an investor with 40% of BridgeClimb, the Business that operates walking tours over the Sydney Harbour Bridge. BridgeClimb itself made an estimated $10 million profit in 2002. He also invested in Network Ten, the television broadcaster, selling out of his stake with a profit of around $100 million. Cowin is also an investor in the Lone Star restaurant chain in Canada.

Cowin was listed on the Australian BRW Rich 200 list at number 70 in 2008, and 79 in 2009, and had an estimated net worth of A$486m and an estimated value of A$538m in 2010.

He is a member of the board of Directors of Network Ten. He is also a Director of the Sydney Olympic Park Authority, a Director of Chandler McLeod Recruitment company and recently July 2012 joined the board of Directors of Fairfax Media. Cowin is an active member of the World Presidents Organization. He lives in Sydney with his wife, with whom he has had four children.

Cowin was ascribed a net worth of A$1.8bn (24th) in the 2016 BRW Rich 200. Despite this, in 2017, he has been noted for his miserliness with regards to weekend worker penalty rates within Australia, regarding them as a "thing of the past".