This study examines the influence of consumer nationalism on corporate reputation as well as consumer behaviour in China, with a particular focus on Nongfu Spring and its CEO Zhong Shanshan. Through sentiment and textual analyses of social media discourse, this study examines how nationalistic sentiments and perceptions of patriotism influence public opinion, especially when corporate behaviour or affiliations appear to conflict with national interests. The study finds that what Chinese nationalists perceive as unpatriotic behaviour or affiliation with foreign elements may cause significant backlash. This is illustrated by the negative reaction to Nongfu Spring’s suspected Japanese cultural elements in the brand and the CEO’s son’s US citizenship. The findings highlight the complexity of consumer nationalism in China, where economic behaviour is heavily politicised and closely linked to notions of national loyalty. In a market environment where nationalism is prevalent, this study contributes to an understanding of the intricate relationship within nationalism, corporate reputation, and consumer behaviour.