This study examines the relative impact of conscientiousness and cultural capital on academic achievement among university students in Hong Kong, within the broader East Asian educational landscape. Focusing on objectified, embodied, and institutionalized forms of cultural capital, we use fixed-effect hierarchical regression analysis to assess their influence on students’ GPA, while controlling for academic effort, attitude, and socio-economic background. The findings reveal that objectified and embodied cultural capital have limited effects on academic success, indicating that traditional cultural assets such as classical literature or highbrow cultural practices play a minor role in this context. Conversely, institutionalized cultural capital, including recognized qualifications, shows a modest positive association with GPA, though its significance diminishes when other factors are considered. Most notably, the study underscores the dominant role of conscientiousness—reflected in students’ academic effort and attitude—as a stronger predictor of academic achievement. These results challenge conventional views on the primacy of cultural capital in education and advocate for policies that prioritize the cultivation of personal attributes like conscientiousness alongside cultural knowledge to enhance academic outcomes in East Asia.