This paper examines linkages between diverse experiences of trauma and the subsequent pursuit of social activism. Using illustrations from a qualitative study sampling 10 social activists, it explores the advent of activism in the wake of significant trauma experiences they have endured. Drawing on psychoanalytic theory, the concept of “witnessing” was applied and three modes of witnessing were proposed to suggest potential psychic states and mental processes that are ignited within and through activism, which may facilitate processes of trauma transformation, subjectivity formation, and psychic aliveness. Consistent with dialectic tensions underlying trauma experiences, activism may also engender stagnation and re-traumatization.