The importation model is a venerable theoretical explanation for inmate misconduct but it has not been extended in nearly 50 years. The current study advances a life course importation model of inmate behavior where life events in childhood cascade to predict antisocial behavior during adolescence and misconduct occurring during periods of confinement. Based on data from 2,520 institutionalized male delinquents, ordinary least squares, logistic, and negative binomial regression models indicated that family background variables were largely predictive of multiple facets of delinquent careers. Negative binomial regression models of institutional misconduct indicated that proximal delinquent career variables were more consistently associated with misconduct than distal family background factors. Because institutional behavior can be understood as the importing of family deprivation experiences and chronic delinquency, the life course importation model is a useful conceptual framework to study crime over the life course, even including periods of confinement.