This paper takes a transregional approach to examine primary historical sources that reveal the significance of the experiential and professional meanderings of Chua Boon Hean (1905-1995) for Southeast Asian studies. Chua was a writer and artist who emigrated from Chaozhou in southern China to Malaya in the 1920s. He became a prominent figure in the film industry and is recognised as a cultural icon of post-independence Singapore. Chua’s story calls for a careful re-examination of the ambiguities and connections between ‘diaspora’, ‘ethnicity’ and ‘borders’. While policymakers had reasons to adopt such labels to manage a diverse population in a colonial and post-colonial setting, researchers must recognise the limits and implications of such efforts. Experiences of social belonging and ethnic identity – more malleable than categories might allow – repudiate this approach of rigid labelling. By adding new dimensions and fresh primary sources from Chua’s archive to ongoing discussions in Southeast Asian studies, this paper illuminates the fluidity of Chinese diasporic networks and ethnic identity overseas. By examining Chua’s story through a transregional historical lens, this paper lays the groundwork for a more imaginative approach to understanding the elastic and fluid process of identity formation in modern Asia. Such a perspective can contribute significantly to the current climate of heightened mobilities and politicised exchanges in Southeast Asia.