This research examines the subjective dimensions of intra-EU labor mobility among staff working for decentralized EU agencies located in Greece (Cedefop), Ireland (Eurofound) and Italy (European Training Foundation), and the development of their identity, interculturality and career capitals. The qualitative data for this doctoral dissertation were gathered through thematic interviews held individually with a total of 20 interviewees at the above agencies. The results show that the participants seem to have been attracted by the intercultural aspects and career opportunities of the European Union agencies. They addressed their body of knowledge (career capital) more from person-centered than contextual perspectives. So, personal motivation, professional competences and social networks were assets discussed in more depth in relation to their global careers. In general, respondents were constructively critical about how professionalism is expressed in an international work environment, and how interculturality and Europeanness are demonstrated. They occasionally questioned what it means to be intercultural or to feel European. The respondents appeared to be aware of the complexities of identifying themselves as European, even though they feel it is an essential aspect of who they are and what they are supposed to represent in their professional roles. The common characteristic of identity, interculturality and career capitals seems to be their processual, interactional and contextual nature. The results suggest that in an international professional environment the investigated capitals are closely intertwined. They express themselves differently depending on prevailing conditions, and respond to various circumstantial factors usually in a flexible way. Perplexities and uncertainties experienced around interculturality originated usually from the need to have one’s referential frameworks modified and related identifications adapted to living abroad and working at a supranational level. The interviewees seem to have developed their sensitivities towards diversity and their ability to interact in a constantly transforming international environment, but they seem to lack tools, even knowledge for more profoundly understanding how to cope with these capitals.