The higher relevance that the European Parliament (EP) has gained in the last decade has made the EU a more attractive venue for ambitious legislators. At the same time, increasing professionalization and lower turnover rates have boosted the EP’s institutionalization. These changes prompt us to investigate which are the ‘roots’ of this professionalization process at the individual level and how they affect the definition/recruitment of the institutional leadership within the EP. For this reasons, the paper tackles these issues by focusing on European parliamentary elites. In particular, we aim to contribute to the literature on European career paths reflecting on the existence of a structured core group of MEPs, who represent the internal leadership inside the EP. We will do so through an analysis of the selection mechanisms that can explain the appointment of specific political profiles to leadership positions. Our main questions are ‘how do national and European political experiences impact on the assignment of top positions in the EP? Is there a connection between past political experience and leadership positions within the EP? We specifically look at committee chairs, rapporteurs, and parliamentary party leaders. We propose an integrated theory of appointments in the EP, based on the principal-agent framework. We argue that principals can value the same previous experience differently, depending on the very function that the agent is supposed to fulfill in the EP (i.e. top leadership positions should be assigned to those MEPs with the strongest political background). The analysis covers the 2009-2014 and 2014-2019 legislative terms and it is based on an original dataset on the careers and roles of all MEPs