As mobility is increasingly reshaping social relations, understanding how it affects new forms of social exclusion is an important challenge in today's polarized societies. From a political-psychological perspective, this challenge requires recognition of how identity processes linked to exclusion are significantly shaped by sociospatial mobility practices. Identity, mobility, and exclusion are at the core of the psychological experience of people living in segregated areas from where they are impelled to leave. Building on this argument, we present a qualitative case study based on ethnographic and narrative methods, which aimed to understand identity processes among young people who have lived most of their lives in four "stigmatized neighborhoods" in Santiago de Chile. The analysis indicated that young people navigate a paradoxical identity project in such neighborhoods, driven by contradictory cultural mandates. This case study contributes to knowledge on how sociospatial exclusion and the politics of mobility can manifest in the form of "identity trouble," as young people struggle between belonging and running away, while attempting to maintain a coherent sense of self.