This article examines the dynamics of heritage language (HL) identity development by analysing the life history accounts of three Chinese heritage language (CHL) learners growing up in the UK. Drawing on narrative data, the study contributes to the growing body of HL identity research by capturing the individual trajectories of CHL learners engaging with different interlocutors, at multiple sites, and across the lifespan. We report the various ways our participants are positioned by the essentialist discourses of Chineseness and how they learn to (re)position themselves as competent HL learners and legitimate members of the diasporic community. The findings highlight the need to understand HL learners' identity and agency as emergent from varied social interactions embedded within one's personal history. In light of the findings, we propose an original model to theorise the dynamics of HL identity development from a historical, spatial, and relational lens, and conclude with practical suggestions to encourage HL learning and maintenance.