Against the backdrop of the worldwide prevalence and importance of internationalisation in higher education, the mixed-methods study examined the relationships between tertiary-level learners' on-campus intercultural activity participation (e.g. intercultural talks and workshops), seven aspects of whole-person development (civic responsibility, cultural engagement, intellectual capacity, peer relationship, community care, leadership, and self-appreciation), and academic performance. A questionnaire was distributed to 518 participants studying at two universities in Hong Kong. No positive relationship was found between participation and academic achievement. However, participation was positively correlated with all aspects of whole-person development. Community care and cultural engagement had the strongest correlations with participation. Following an explanatory sequential design, 18 of these participants were invited for a follow-up interview to expound on the findings based on their experiences, observations and understanding of their peers. The article ends with a discussion of the findings and implications for intercultural learning and teaching in higher education.