In 1881, Cowan purchased land near Murray Bridge, South Australia which he would develop and retain until his death.

[1][2] Cowan served as a councillor on the District Council of Mobilong from 1892 to 1912 including the role of chairman from 1896 to 1912.

He also served as the Government Whip in the Legislative Council for a period of 20 years and as a member of the Parliamentary Standing Committee on Public Works from 12 July 1934 to 31 May 1944.

[4] He rode a hack around his property Glen Lossie near Murray Bridge, up until his death on 8 March 1953(1953-03-08) (aged 86) and was survived by his wife Elizabeth and their children.

[3] His contribution to public life was recognised with the conferral of the prefix 'Honourable' on 7 August 1930 and a Knight Bachelor on 1 January 1944.