In the early 2000s, governments’ need to understand and prevent the process of radicalization and violent extremism created a strong demand for knowledge. Within a few years, a new field was developed within a range of formal institutions, including governments, universities, the media, and outside of it by private and nonprofit sectors. In this paper, we will address three objectives: (1) identify radicalization and violent extremism expertise types; (2) analyze the specific objects, subjects, and clients; and (3) map the various types of expertise by identifying the particularities of each. The data was collected from experts’ and governments’ reports and websites and interviews with 15 academics, experts, or policymakers from 2018 to 2020 in Europe. Following the expertise theory of Eyal and Pok and the mapping method of Medvetz, the model shows that competition and cooperation between experts lead to different types of expertise, where each has its own goals, type of initiative (outcomes), and agenda in their pursuit of funding and authority in the field. This clarification of roles, tensions, and collaborations among government entities showed that the ambiguity between types of expertise should be viewed as a productive aspect of the field. The study concludes that our model can assist policymakers in understanding the mobilization of expertise.