During their early political socialization young people start to recognize their agency as political actors and to develop their political identity. This article presents the findings of a comparative study across different types of youth activism in two cities, Athens and Cologne, which differ in their youth cultures of participation and the opportunities they provide to mobilize. Our data derive from in-depth qualitative interviewing, which is considered to be most fruitful for the exploration of the reasons behind activists' trajectories. We identified three groups of influences: micro-, meso- and macro-level influences, with micro-level influences being most visible in the path of social movement-related activism, meso-level influences being dominant in the path of partisan activism, and macro-level influences prevailing in grassroots activism. Finally, the implications of the differential impact of the studied socio-spatial contexts are critically discussed.