The concept of American exceptionalism has permeated U.S. history and created an image of a country with better democratic system and society, able to promote domestically and internationally the democracy, human rights and the rule of law. This idea has legitimatized U.S. leadership in the construction of a liberal international order. The rise to power of President Donald Trump and the current crisis of the global order have contributed to question this idea and assumptions. This dissertation has two main aims, firstly, to discuss the concept of American exceptionalism, and secondly to analyse how the concept of American exceptionalism affects the relationship between the United States and International Law. It will be argued that exceptionalism can be defined as a concept and analysed with the theoretical and methodological lenses of Conceptual History. With no definitive meaning, American exceptionalism is made of different interpretations that vary across the context the author was situated in. Still, its importance in American history and identity is unquestionable, making it necessary to take exceptionalism into account when trying to understand the United States actions. In order to analyse the relation of American exceptionalism and International Law, the dissertation will engage with the literature of International Liberal Order, U.S. hegemony and multilateralism. Furthermore, it will inquire if the rise of Donald Trump can be considered a rupture in two American traditions: the United States relationship with International Law and the political use of exceptionalism. It is argued that, although clearly distancing himself from the exceptionalist tradition, Trump did not deviate from International Law tradition as it is commonly perceived. This perception is derived from his radical speeches, loud personna and ties to the Far-Right, but do not translate into most of his policies.