Tremblay was president of the Société canadienne de science économique (1974–75) and of the North American Economics and Finance Association (1986–87).

He is also a Quebec nationalist who attempted to reconcile the need for economic integration, economies of scale, increased productivity, an active industrial policy, and political and cultural sovereignty for small nations.

(1) In 1986, when Prime Minister Brian Mulroney, a politician from Quebec, announced that his Progressive Conservative government would formally propose a Free Trade Agreement with the United States, Tremblay became president of a committee of Canadian economists to support the measure.

The committee rallied a large number of Canadian economists behind the policy, and it met with Prime Minister Mulroney on April 25, 1988.

Later, Tremblay opposed the creation of a North American Union, (NAU) which would have further deepened the economic integration of Canada to the United States, and could have placed Canadian independence at risk.

In 1987, when the federal government under Prime Minister Brian Mulroney introduced the Meech Lake Accord, it included some of Tremblay's ideas about political decentralization.

In 2003, his book entitled Pourquoi Bush veut la guerre, Religion, politique et pétrole dans les conflits internationaux, published more than one month before the event, dealt with the March 20, 2003 American-led invasion of Iraq.

(21) The book codifies in a pedagogical way the most fundamental humanist principles of rational ethics with the objective of reconciling private and general interests in human interactions.

The themes range from human dignity, human life, tolerance, the need to share, and the requirement to avoid domination and superstition, to the preservation of the Earth's natural environment, the issue of violence and wars, the question of political and economic democracy, the separation of Church and State, and the central role of education and knowledge as gateways to personal happiness, independence, and individual freedom.

Critiques of Tremblay's book about ethics have hailed it as either a "solid, historical argument and proposals for integrating humanist philosophy into both our everyday lives, and our social institutions" (David Koepsell) and as "a rational jumping-off point toward a new society" (Victor J. Stenger), or rather, as being a "too ambitious" project (Jan Czekajewski) or as "worthy ideals grounded in the very theories that were called upon, historically, to justify atrocities and undermine peace" (Wendy C. Hamblet).