The decisive nature of the new structural and contextual forces and their deleterious effects on health and well-being of individual’s who attempt to adapt themselves require the development of research and intervention practices that can transform contexts of life and work. In this sense, various actors highlight the importance of advocacy in the field of counseling. In regard to the guidance domain, advocacy involves actions aiming to remove systemic barriers that hinder the capability of finding one’s path, including measures that directly discriminate marginalized populations or that limits fair access to high-standard guidance services. Advocacy as a professional activity is not formalized in Quebec (Canada) and little is known on the ways it integrates itself in daily professional practices. Based on a qualitative research conducted with school counselors in Quebec, this study analyzes their work of advocacy pursuit as an activity of world transformation in a social justice perspective. The theoretical and methodological framework of this study are based on a cultural-historical activity theory, for which labor is the fundamental human activity, the one that changes nature, as well as creates culture and human beings (Dionne & Jornet, in press). Data analysis underline the particular way school counselors perform advocacy in line with their « professional genre » (Clot, 2014). Three themes emerge from the analysis in regard to the advocacy actions and the implemented conditions: 1) the alliance with the influential actors; 2) the construction and the upholding of credibility; 3) strategic expertise. Individual and collective consciousness of these resources can enhance school counselors’ power to act in their work and therefore foster the development of an inclusive society.