It is well known that the Neo-Confucian thinker Zhu Xi (1130–1200) particularly emphasizes the role of emotions in human life. This paper shows that the four ‘moral emotions’ (e.g. feelings like ‘compassion’ and ‘disdain’ as described in the Mencius) are central to Zhu's thinking, insofar as only their genuine actualization enables the individual to achieve spiritual freedom. Moreover, I discuss the crucial notions of ‘awareness’/‘perception’ (zhījué) and ‘knowledge’/‘wisdom’ (zhī), in order to reveal the complex dynamic that moral emotions are said to create in the moral agent. I also analyse two important passages from the Mencius (1A/7 and 2A/6) and examine how Zhu Xi, in his exegetical glosses, defines the conditions of virtuous agency as based on the moral emotions. Finally, I explain the reasons why Neo-Confucians like Zhu Xi have sometimes been described as Kantian thinkers avant la lettre.