He served in the Legislative Assembly of Alberta from 1955 to 1975 as a member of the Social Credit Party.
Ruste served as a cabinet minister in the governments of Premier Ernest Manning and Harry Strom from 1965 to 1971.
[4] Premier Ernest Manning appointed Ruste to the Executive Council of Alberta on February 16, 1965 as the Minister of Lands and Forests.
Ruste ran for a fourth term in the 1967 general election and won a straight fight against NDP candidate Glenn Valleau with almost 85% of the popular vote.
Ruste ran in the 1971 general election and won by another landslide in his district even as the Social Credit government was defeated.