From the end of the 1960s until the outbreak of the Civil War (1975), Lebanon experienced a phase of relatively sustained industrial expansion. Albeit the “boom” did not modify significantly Lebanon's tertiarized economic structure, it was anyway sufficient to create the structural conditions for the emergence of a new militant working-class able to become one of the most relevant contentious actors of its time. This new working class was made primarily of very young and recently urbanized unemployed of rural origin, brutally injected in a crude and hyper-exploitative productive cycle where formal labor unions were, for the most part, absent or scarcely effective. The input for their grassroots, transgressive organization into factory-based Workers’ Committees came from the Organization for Communist Action in Lebanon (OACL), i.e. the most important force of the so-called Lebanese New Left, within the framework of a broader process of militant penetration of the “revolutionary classes” produced by the contradictions of Lebanese capitalism. This created the precondition for the Committees to affirm themselves not only as the radical avant-garde of the Lebanese labor movement but also as an integral part of a broader process of contestation of the existing status quo by the subaltern groups emerged from - or activated by - the structural and cultural changes that the country was experiencing. By retrieving the forgotten history of the Workers’ Committees, the article wants to examine the forms and the trajectories whereby such a new working class became an integral part of this process. In particular, by adopting a Gramscian methodology, the article will first expose the structural changes in the Lebanese industrial sector in the examined period and their labor implications. Then, it will focus on the dynamics which superseded the Committees' birth and affirmation, reserving particular attention to the role played by the OACL. Finally, it will conclude by examining the impact of their agency on the political developments that the country was experiencing. The paper contends that the emergence and the affirmation of counter-hegemonical and transformative working-class activism on the eve of the Civil War, along with representing a direct by-product of structural stresses and constraints, was significantly debtor also of the new ideological and militant infrastructures that the emergence of an Arab New Left had contributed to popularize and deploy. The paper wants also to intervene in the historiographical debate on the Lebanese Civil War, stressing the importance of both subaltern actors and class phenomena in its outbreak, which have generally been widely disregarded by the dominant understandings of the conflict.