Born in Wallaroo, South Australia on 3 January 1882, he was the son of farmer Robert Cowan and Christina née McMartin.
Cowan spent most of his life prospecting for gold on the north-eastern goldfields of Western Australia.
In 1828 he was working as a barman when he successfully contested a Legislative Assembly by-election for the seat of Mount Leonora on a Labor ticket.
In that election he contested the seat of Mount Magnet, but was defeated by the Labor incumbent Michael Troy.
In the general election of 29 April 1944 he contested a Western Australian Legislative Council North East Province seat as an Independent Labor candidate, but was unsuccessful.