Abstract: This article explores why the figure of the child soldier as an abused and exploited victim of war erupted to the forefront of humanitarian and human rights advocacy in the 1990s, arguing that a humanitarian calculus of concern constructed this “child soldier crisis.” It analyzes the structural and contingent factors that drove the development of transnational advocacy from initial concerns in 1969–71 to the 2000 Optional Protocol on the Involvement of Children in Armed Conflict. The article highlights the successful campaigning tactics of these networks, showing how the object figure of the child soldier as victim was framed by racialized and paternalistic tropes of Global South societies and shifting constructions of childhood itself. It is based on extensive research across UN agency and INGO archives, private papers, media sources, and human rights reports.