Born in Adelong, New South Wales, he was educated at public schools and then at Kings College, Melbourne.

He became an insurance agent and then a station owner in Western Australia, where he eventually became a Perth City Councillor, serving as Mayor 1913–1914.

Prowse transferred to the new seat of Forrest in 1922, allowing party colleague Henry Gregory (member for the abolished Dampier) to contest Swan.

He was also a grandmaster in the Orange Order and "busy in the early organisation of philanthropic causes in Perth, including the Blind and Deaf and Dumb Institutions, and the Children’s Protection Society".

[2] In 1913, Prowse was elected to the executive of the newly created Farmers' and Settlers' Association of Western Australia (FSA).

Both Prowse and Nairn resigned in June 1943 to support a motion of no confidence in the Curtin government, but were themselves defeated in the ALP landslide victory at the 1943 election.

He was widowed in 1939 and remarried in 1941 to Jean Murdoch, with his parliamentary colleague Harold Holt serving as best man.

[2] In 1910, Prowse went into partnership with his brother Albert and purchased Wallatin station, situated in the Wheatbelt north of Doodlakine.