This dissertation sets its objective as studying Celal Bayar‟s leadership from 1937 to 1960 in order to present the portrait of Bayar as a political leader. The interactive approach is employed to structure this analysis. In line with this approach, external and internal resources of Bayar‟s leadership are defined. External resources are considered with regard to institutional and non-institutional aspects. The non-institutional resources referred to are the main characteristics of economy, of international relations and of political regime in 1937-1960. Institutional aspect of Bayar‟s leadership in 1937-1960 is studied with regard to executive offices he held. With regard to the internal resources of leadership, the effects of certain life experiences on Bayar‟s politics and his understanding of major political concepts such as democracy and secularism are discussed. Primary and secondary resources, as well as interviews with his close circle provide the material for this study. In the conclusion part, the impact of certain internal resources on his leadership, such as his commitment to the main principles of the Republican regime is acknowledged but it is pointed out that external resources, such as Atatürk‟s trust in him, had a greater impact on his leadership. It is also observed that the portrait of Bayar as a political leader falls in a category in between a state elite and a political elite. Regarding the interactive approach, it is concluded that under non-institutionalized regimes, the institutional offices lose their defining characteristics on leadership and that other resources such as the leader‟s relations with other leaders and his/her interpretation of political office gains extra emphasis.