Clark ran as a Liberal candidate in the Rosebud electoral district in Alberta's first provincial election after it was admitted into Confederation, in 1905.
Clark ran for his second term in office in the 1911 Canadian federal election; this time, he defeated Conservative challenger and future Member of the Legislative Assembly (MLA) Alexander McGillivray.
In 1917, he ran for his third term in office as a supporter of the Unionist government and was successful, defeating former Alberta MLA William Puffer.
Clark joined the Progressive Party of Canada in 1920 but returned to the Liberals just a year later due to his opposition to class-based politics practised by the United Farmers of Alberta.
He ran for the Liberals in the Mackenzie electoral district in Saskatchewan in the 1921 Canadian federal election but was defeated by Progressive candidate Milton Neil Campbell and lost his seat.