Résumé : This present research was driven by the observation of a thought-provoking puzzle, which came from the examination of the literature concerning the regional leadership roles of Brazil and Germany. In this regard, Brazil was often classified as a “consensual hegemon” (Burges 2008) and a “leader without followers” (Malamud 2011). In its turn, the literature labelled Germany as a “reluctant hegemon” (Paterson 2011) and as a “benign hegemon” (Morisse-Schilbach 2011). In this context, authors argued that Brazil claimed for being a leader in South America, but failed to count on the support of its neighbours. According to a large part of the literature, Germany was asked by its European peers to act as a leader, but eschewed from recognizing itself as one. Hence, the research puzzle came to fruition - in matters of being a regional leader, a contrast was found between Brazil and Germany that no other countries in their respective region presented: Brazil wanted it, but could not have it; Germany had it, but did not want it. Thus, the quest for explaining this puzzle guided this doctoral thesis. But rather than focusing exclusively on which role(s) both countries played in their region or even disputing the existing categories of roles created by the literature, this research delved on examining the elements that influence the development of potential role(s) by examining the creation of national role conceptions. In this sense, the research question presented here is of how National Role Conceptions were developed in relation to MERCOSUR and the EU during the mandates of Lula (2003-2006) and Merkel (2005-2009), respectively. The study of role conceptions is embedded in the framework of Role Theory, and the national role conception flowchart originally conceived by Breuning (2011, p.26) was tested by this research as a theoretical model. Adopting a constructivist ontology and an interpretivist epistemology, this research assessed with the help of Narrative Analysis 70 speeches delivered by Lula and 104 speeches given by Merkel during the selected timeframes, in order to investigate identity narratives concerning their respective countries and regional institutions. Database from Latinobarómetro, Eurobarometer, and the World Bank were also employed. The results obtained by this research when applying the analytical flowchart proposed by Breuning (2011, p.26) explain the research puzzle: Brazil cannot have reginal leadership because it does not perform it when the opportunities to act arise; and Germany does not want regional leadership because it is not aligned with its identity and cultural heritage. Furthermore, the main findings reveal that Brazil performed a discursive leadership, while Germany enacted a de facto leadership. Neither country combined both types of leadership when acting regionally.