Internationalisation has recently become one of the major developmental goals within many institutions of higher education, where the use of languages on campus plays an important role. While research focusing on the use of English in higher education is growing, little attention has been paid to out-of-class contexts. This paper reports on the identity formation of an undergraduate who lived in a multicultural residential hall on an English-medium campus in Hong Kong through ethnographic narrative inquiry. The combination of ethnographic observations and informal talks with the participant in the research field for a two-year period, the participant's Facebook posts and photographs as records of his hall life and three intensive face-to-face interviews generated rich data for the inquiry. The participant was described as a local-non-local "hybrid" because of his dual identity of being both local and non-local. Drawing on Wenger's framework of social theory of identity formation, this paper revealed the challenges of internationalisation in higher education through the perspective of the "hybrid" with both local and non-local identities. An important implication arising from the study is the need to take a closer look at cultural integration and internationalisation in out-of-class contexts.