He was one of the organizers of the Saskatchewan Grain Growers Association and was elected its first president, a post he held from 1910 to 1923. To give farmers some say in the marketplace the S.G.G.A. obtained Saskatchewan government loans to build farmer-owned grain elevators. The Saskatchewan Co-operative Elevator Company was formed to operate these elevators and Mr. Maharg again was first president. Within 15 years the company had 450 country elevators, two terminals and it ran a grain exporting business. Mr. Maharg also served as president of the Canadian Council of Agriculture from 1915 to 1917.

In 1917 he was elected Member of Parliament for Maple Creek as an Independent supporting the wartime Unionist government. A year later he crossed to the Opposition with a group that was to help found the Progressive party. In 1921 he left federal politics to become Minister of Agriculture for Saskatchewan. He ran and was elected provincially as Independent member for Morse constituency. He continued in the cabinet until fall when he resigned in a confrontation which also resulted in the resignation of Premier W. M. Martin. From then until 1924 when he left political life Mr. Maharg served as leader of the Opposition.

Returning to his farming and off-farm interests, he represented the Co-operative Elevator Company on the provisional board of the newly-formed Saskatchewan Wheat Pool. Mr. Maharg remained active with the Co-operative Elevator Company until its assets were sold in 1928 to the Pool. He then returned to farming and remained there until his death in November 1944.