Ferguson is a farmer in south-western Ontario, and co-founder of the Lambton Pork Producers Association. In the late 1950s, he was chairman of the Lambton County Egg Producers.
Fergurson served as parliamentary secretary to the Minister of State for Small Businesses and Tourism from 1980 to 1982, Deputy Government Whip from 1982 to 1984, and parliamentary secretary to the Minister of Finance from March to June 1984.
When John Turner succeeded Pierre Trudeau as Liberal leader and Prime Minister of Canada, he brought Ferguson into the Cabinet as Minister of Agriculture, succeeding long-time Trudeau Agriculture minister Eugene Whelan.
Ferguson's cabinet career was short-lived, however, as both he and the Turner government were defeated in the September 1984 federal election.
As a backbench MP, Ferguson participated in several trade missions as an advocate of export market expansion. He also played a role in the creation of the Canadian Agricultural Export Corporation or CANAGREX, a crown corporation formed in 1983 and disbanded by the Mulroney government in 1987. As minister, he established the first controlled environment seed bank in an effort to protect parent seed stocks.
He was successful in his attempt to return to the House in the 1988 federal election having campaigned strongly against the Canada-US Free Trade Agreement. Ferguson did not run in the 1993 federal election, preferring to retire from politics and return to the farm where he has been an active conservationist. He is also an environmentalist and advocate for renewable energy.