This paper introduces biographical criminology as an emergent theoretical framework that examines how institutional gaps in service provision create cumulative vulnerabilities to criminalisation across individual life courses. Unlike traditional criminological approaches that focus on discrete criminal events or developmental pathways, biographical criminology investigates how failures in education, healthcare, social services, and welfare systems compound over biographical time to systematically channel certain populations toward criminal justice contact. Drawing on life course theory, narrative criminology, and institutional analysis, this framework reveals how seemingly legitimate administrative processes constitute forms of "biographical injury" that accumulate across decades. Through theoretical exposition and empirical illustration, this paper demonstrates how institutional gaps create temporal vulnerabilities that make criminalisation appear inevitable whilst obscuring the systemic processes that produce this outcome.