Cowan was an active sports participant in the district, playing and coaching local football, tennis, golf and basketball clubs.
Representing the National Country Party (NCP), he defeated Labor's James McMillan Brown in the March 1974 election for the seat of Merredin-Yilgarn.
Liberal Premier Sir Charles Court dominated conservative politics during the period and the rural party was seen as having only minor influence.
[8] The conservative parties were in opposition through most of the 1980s with Labor yet to suffer from major fallout from the WA Inc fiasco and the 1987 stock market crash.
In 1989 Liberal opposition leader Barry MacKinnon was pushing for the Nationals to help block supply in the Upper House to topple the Dowding government.
In February the following year, Cowan and the Nationals had reversed their stance and decided to block supply in a bid to present themselves as a decisive and consistent conservative force.
After his retirement, Cowan re-established himself at his farm in Narembeen as well as taking appointments on a number of boards including: In 2003 he was awarded an Honorary Doctorate in Science from Murdoch University.
In 2007 he was appointed to conduct an independent review of the West Coast Eagles Football Club, with Steve Scudamore from KPMG.