He arrived in Calgary in 1906 and started working for the Crown Paving Company Limited.

On July 19, 1919, in his first year as mayor he married Daisy Mary MacGregor, the City Hall reporter for the Calgary Herald.

Marshall would spend three years serving as an Alderman on Calgary City Council.

Marshall would serve as Mayor of Calgary for two years, first contesting the 1918 Calgary municipal election defeating opponent and incumbent Mayor Michael Copps Costello with 3,428 votes, a slim margin of victory of 194.

He won a provincial seat to sit as MLA for Calgary electoral district.