Why has China's foreign policy become more assertive since 2009, and what is driving Beijing's foreign policy orientations? Given the significance of China's rise over the past few decades, it is surprising that this question has not been subjected to systematic analysis as well as general investigation within scholarly research. This article serves to examine the sources of China's assertiveness using a system‐level, unit‐level and individual‐level analysis. This article first looks at system‐level explanations such as state power, external threats and national interests, and then considers unit‐level factors including bureaucratic competition, struggles of the elite and the surge of nationalism. However, both system‐level and unit‐level explanations alone fail to account for China's more assertive foreign policy. This suggests that individual factors play a major role in explaining the country's more assertive external behaviour. This is especially the case when the perceptions of the political elite are deeply embedded in the state leader's preferences. This finding can enhance our understanding of why traditional explanations, that do not incorporate the role of the state leader, may fail to predict Chinese foreign policy behaviour. To understand better the implications of China's rise, therefore, we must take into account the role of the state leadership and its impact on China's growing influence in international politics.