Industrial disputes opposing major restructuring projects are often intense. To understand the construction of these forms of resistance, we rely on the life histories of thirty-five union activists who have led struggles against major restructuring projects. In a situation of high tension with important issues in terms of control of actions by the union activist, maintenance of employee mobilization, potential differences on the aims of the struggle, but also of ways of reconciling personal and activist lives for the leader himself, it appears that open, hidden, collective, and individual actions are articulated to organize resistance. This organization is based on the constitution of a network, on devices for interaction with employees, and on a small team of trustworthy individuals. This raises finally the question of the individual and contextual factors which seem to favor the emergence of these resources.