He served in the Legislative Assembly of Manitoba from 1953 to 1962 as a Progressive Conservative, and held several cabinet posts in the government of Dufferin (Duff) Roblin.

Shortly after marrying Lorraine Dutton of Virden in 1942, Thompson joined the Royal Canadian Air Force and for three years was a leading airman during the Second World War.

[2] When Duff Roblin assumed the party leadership the following year, Thompson was a key voice of the opposition attacks during the 1956 beer price debate, the oil lease scandal of 1957, and was a sharp critic on penal reform.

With 64% of the vote Thompson was re-elected in a redistributed Virden constituency, where he defeated the Liberal-Progressive incumbent Francis C. Bell.

At the end of March 1959, following heated debates regarding the upcoming fiscal budget, the government lost the confidence of the legislature and fresh elections were called for June.

Easily re-elected in the May 1959 election with 68% of the Virden vote, Thompson continued to hold his Labour and Municipal Affairs portfolios.

Willis resigned his office on December 21, 1959, and Roblin then appointed Thompson to move from Labour and pick up the Public Works portfolio.

In February 1963 now Judge Thompson was appointed as a Commissioner to the Manitoba Royal Commission on Local Government Organization and Finance, at that point to be chaired by Roland Michener.

After Michener was appointed High Commissioner to India in 1964, Thompson took up the Chair of the Royal Commission and issued their final report in August of that year.

Judge Thompson continued to serve the southern and eastern Manitoba judicial districts for more than twenty years, retiring from the bench in 1983.

For his achievements Thompson is a member of the Brandon University Alumni Wall of Fame,[7] and recognized as a 'Memorable Manitoban' by the Manitoba Historical Society.