In recent years, a dominant discourse has emerged asserting that humanitarian work has become a dangerous profession. In response to growing insecurity in the field, humanitarian organizations have come to develop new security policies to better protect humanitarian staff and infrastructures. Drawing from Andrew Abbott's historical sociology of professions and Pierre Bourdieu's social theory of power, this thesis proposes an international political sociology of the professionalization of humanitarian security. To address the shortcomings of normative-functionalist explanations and poststructuralist critiques of humanitarian security, this thesis examines the conditions of possibility fostering the emergence of a microcosm of humanitarian security professionals. As a consequence of this seemingly insignificant transformation in the division of humanitarian labor, humanitarian organizations now classify some of world's neediest populations as beyond the limits of reasonable sacrifice. In the production of this exclusion, humanitarian actors reconstruct “populations in need” as “dangerous populations.” By weighing the cost of the loss of a “humanitarian life” against the potential value of saving the lives of needy others, humanitarian actors contribute to the intensification of global divides in their quest for a common humanity. In sum, the imposition of security as a humanitarian logic of practice is analyzed as a driving force of the inversion of the humanitarian imperative to save lives and act in defense of a shared humanity. While contributing to debates on humanitarian security, this thesis also contributes to the study of international organizations, security, and transnational power elites.