McFadden was a Conservative, and served as a cabinet minister in the governments of Hugh John Macdonald and Rodmond Roblin.

The Conservative Party assumed office on January 10, 1900, and McFadden was appointed as Minister of Public Works and Provincial Secretary.

When Rodmond Roblin replaced Macdonald as premier on December 20, 1900, he reassigned McFadden as Municipal Commissioner and Provincial Secretary.

He was re-elected over Liberal George Walton in the 1903 election, and might have lost had the opposition vote not been split with a Prohibitionist candidate.

In 1915, the Roblin administration was forced to resign from office after a report commissioned by the Lieutenant Governor found the government guilty of corruption in the tendering of contracts for new legislative buildings.