Theory suggests people high in socially prescribed perfectionism become depressed when they encounter ego-involving interpersonal problems. Prior studies testing this theory produced mixed results. The present study improves upon past designs by incorporating ego-involving life events from participants’ autobiographical narratives. Specifically, it was hypothesised that friendship intimacy, as coded from narratives, would moderate the relationship between socially prescribed perfectionism and depressive affect. Young adults transitioning into university for the first time (N 127; 75.5% women; 81.1% Caucasian) participated in a two-wave, 130-day longitudinal study with quantitative and qualitative components. Entering university is a developmentally important and highly stressful transition for emerging adults. Results showed that socially prescribed perfectionism (but not self-oriented perfectionism) interacted with low friendship intimacy in autobiographical narratives to predict rank-order increases in depressive affect over time. These results advance understanding of the relationship between perfectionism and depressive affect by demonstrating the conditions under which the relationship occurs. The present study improves upon prior research by using a novel, mixed methods approach to operationalize interpersonal problems and by studying a transitional period (i.e., the transition to university) where change in depressive symptoms is expected.