Arriving in Saskatchewan from England in 1902, Dunning soon became a leader in the farmers' movement. After pioneer work on cooperative marketing and farm credit, Dunning became the first general manager (1911- 1916) of the Saskatchewan Cooperative Elevator Company. He urged agrarian groups to avoid third-party politics, and channelled farmers' discontent into support for the Liberal party. In a political career lasting from 1916 to 1939, he was premier of Saskatchewan (1922-1926) and was twice federal Minister of Finance. A successful business career followed his retirement from politics.