This thesis examines the idea that Australian federal political leaders are becoming more powerful. This idea, often referred to as presidentialization, generates heated debates in academic circles. Using one of the more systematic frameworks, namely the Poguntke and Webb (2005) model, and combining a behavioural component, this thesis seeks to explore whether Australian federal politics has become presidentialized. Poguntke and Webb viewed presidentialization as consisting of three separate but inter-related faces. These were: the executive face, the party face and the electoral face. This thesis undertakes this task by examining four leadership periods from the Australian Labor Party (ALP). This includes: The Chifley leadership period (1945-51), the Whitlam leadership period (1967-1977), the Hawke Leadership period (1983-91) and the Kevin Rudd leadership period (2006-2010). In the Chifley leadership period it is argued that very little evidence of the presidentialization phenomenon as described by Poguntke and Webb (2005) is identifiable. This finding adds to their hypothesis that many of the causal factors that contributed to presidentialization did not emerge until after 1960. This section of the thesis also highlights how different Australian society and the ALP were during this period than to the later periods examined in this thesis. The second period, the Whitlam leadership period, is vastly different. Clear increases in the capacity of leaders to exert power began to emerge. Hugely important structural changes to the ALP occur during this period which fundamentally alters intra-party power. Some evidence of leaders being able to exert greater power within the executive of government can also be identified during this period. The elections that Whitlam contested display a mixed level of personalisation.