This chapter presents the analytical framework for studying the political leadership performance of EU Commission presidents. First, it clarifies why European integration theories have proved insufficient in explaining the actual impact and performance of the presidents of the European Commission. Second, it conceptualizes political leadership as a behavioral phenomenon within the field of social interaction and relates it to European governance. Third, it introduces the interactionist approach to analyzing political leadership, focusing on its central variables: (1) personal (pre-)dispositions, (2) institutional structure, and (3) situational setting. Moreover, it develops a typology of patterns of leadership performance and a functional-phases/variable model to operationalize leadership analysis of the Commission presidency. Fourth and finally, it presents the research strategy, encompassing a structured, focused comparison alongside systematic content and discourse analyses for each case under study.