Tremblay's first professionally produced play, Les Belles-Sœurs, was written in 1965 and premiered at the Théâtre du Rideau Vert on August 28, 1968.

It stirred up controversy by portraying the lives of working-class women and attacking the strait-laced, deeply religious society of mid-20th century Quebec.

Tremblay's early plays, including Hosanna[1] and La Duchesse de Langeais,[2] challenged the boundaries of French Canadian society.

[3] Until the Quiet Revolution of the early 1960s, Tremblay saw Quebec as a poor, working-class province dominated by an English-speaking elite and the Roman Catholic Church.

He has been openly gay throughout his public life, and he has written many novels (The Duchess and the Commoner, La nuit des princes charmants, Le Coeur découvert, Le Coeur éclaté) and plays (Hosanna, La duchesse de Langeais, Fragments de mensonges inutiles) centred on gay characters.

[5] In a 1987 interview with Shelagh Rogers for CBC Radio's The Arts Tonight, he remarked that he has always avoided behaviours he has considered masculine; for example, he does not smoke and he noted that he was 45 years old and did not know how to drive a car.

Tremblay also worked on a television series entitled Le Cœur découvert (The Heart Laid Bare), about the lives of a gay couple in Quebec, for the French-language TV network Radio-Canada.

He made it clear, however, that that did not mean that he agreed with bilingualism, calling it "stupid" and stating that he thought it ridiculous to expect a housewife in Vancouver to be fluent in both English and French.

But he clarified his thoughts some time later by saying he was still a supporter of Quebec sovereignty, though critical of the actual state of the debate, which in his opinion was too much focused on economic issues.