This study aimed to investigate the relationship between language exposure and Chinese character handwriting (CCW) among 103 non-Chinese speaking (NCS) students in Hong Kong. Specifically, it examined the impact of academic self-concept, including students’ self-perceptions of their Chinese character competence and affect, on the complex learning process of CCW in a multilingual context like Hong Kong. NCS students were invited to complete a writing-to-dictation test, a questionnaire on CCW exposure outside of the classroom, and a self-description questionnaire of academic self-concept. Path analysis was employed to analyse the path models within the constructs. The results revealed that language exposure had both direct and indirect effects on CCW through academic self-concept. Notably, the effect of language exposure on CCW was strongly mediated by competence self-concept but not affect self-concept. This suggests that NCS students evaluate their competence in producing desired outcomes within exposure environments based on their own self-perceptions. Drawing on these empirical findings, the article discusses the educational implications for Chinese as a second language learning and teaching. It emphasizes the significance of tailored instructional methods that can enhance the competence and affective self-concepts of NCS students. By implementing such approaches, students will be better equipped to integrate into diverse multilingual societies. Copyright © 2024 The Author(s).