His first film with the NFB was Les Raquetteurs (1958). Co-directed with Michel Brault, and including the important contribution of sound recordist Marcel Carrière it surpassed the candid eye approach, establishing for the first time in film history, the filmakers in the midst of the onngoing event. Seeking a truthful relation to the captured film reality, sound is also captured live. The film, not devoid of comical aspects, is also seen as an important step in anthropological cinematography. It captures without judgement, a social phenomenon that would have seemed unimportant in its archaism and triviality (a snowshoe convention on asphalt!), thus revealing with documental distanciation elements of popular Quebec culture that were previously disdained.
In 1961, Groulx's focus shifted from the crowd to the individual, but still showing the individual in his environment.
Voir Miami (1962) revealed Groulx's poetic side. Although it presents an indictment of contemporary America, it does so in a poetic, almost lyrical style.
In 1964, Groulx turned to a highly social and political type of filmmaking, which would be characteristic of his work to the very end. Le Chat dans le sac / The Cat in the Bag, his first feature-length drama, is about coming of age: for the protagonists as they face difficult political choices, and possibly for the Quebec people as well. Not only did Groulx write and direct the film, he also did his own editing (as he would for all subsequent films). In his dramas, Groulx liked to film non-professionals who were the real characters in the story or who were very similar to them and could improvise within a given situation.
Before undertaking another feature, Groulx made the documentary short Un jeu si simple (1965), a dramatic look at Quebec's national sport of hockey.
This was followed in 1967 by the film Où êtes-vous donc?, a complex collage of images reflecting the daily lives of Quebeckers. Groulx questions their choice of lifestyle through an unconventional filmic language giving unprecedented importance to sound. Barraging the spectators with a disturbing mix of chanting voices, songs, quotations and advertisements from the mass media, the film is a protest against the consumer society, a denunciation of the dehumanizing mechanisms created and used by man against man.
Continuing in this pamphleteering vein, Groulx made 24 heures ou plus, a veritable call to revolution, which was censored by the NFB. Shot at the end of 1971, the film was not officially released until 1977, although a bootleg video version of it was seen by thousands of people.
In 1977, he directed the feature-length documentary Première question sur le bonheur, a Mexico-Canada co-production in which Groulx again questions the exploitation of man by man, but this time in the context of rural Mexico.
In 1980, Groulx was involved in a serious automobile accident that put an end to his career, although he did manage to come back in 1982 and complete the feature film he had been working on. Au Pays de Zom is a scathingly funny satire on the businessman ethos in the unexpected form of a musical, in which Joseph Rouleau, an opera singer greatly admired by Groulx, plays the role not of a romantic hero but of a financier.
Groulx's films are the work of a worried man perpetually questioning life and the world around him. Through them, he explored different aspects of Quebec society, always varying his style to suit the subject. He was one of the first Quebec filmmakers to make auteur films, both documentary and drama. Overall, it could be said that his films convey a Marxist philosophy with a Brechtian aesthetic.
In 1985, the Government of Quebec presented Groulx with the Prix Albert-Tessier for lifetime achievement.
"A filmmaker is a journalist: he must inform and comment. For me, what counts in a film is the moral, what the author has to say. Mere technique is meaningless. The story, too, is meaningless; it's the pretext for the film; it's like the model for an impressionist painter." (Translation) - La Crue, September 15 1964
"If my films are defending the freedom of peoples, as a creator I must fight for my own freedom. " - Gilles Groulx