He served in the governing Social Credit caucus during his time in the Legislature representing the electoral district of Olds.
He was handily defeated finishing a distant second to Incumbent United Farmers of Alberta MLA Nelson Smith.
[2] Cook ran for Social Credit nomination for Olds in the 1935 Alberta general election but lost to Herbert Ash who would end up becoming the new MLA.
On election night, Grisdale was leading Cook by 110 votes on the first count, while Ash was trailing a distant third.
Cook continued to gain in popularity, winning a super majority of 74% in his re-election bid for the 1948 Alberta general election.