The Level of Personality Functioning Scale (LPFS) operationalizes Criterion A of the DSM-5 Alternative Model for Personality Disorders (AMPD) model. Yet, research on this measure has been slow to accumulate and questions remain regarding its reliability and validity. The present study examined the LPFS observer-rated (OR) and self-report (SRA) versions of Criterion A in a sample of 240 students who provided psychological life history data and a variety of self-report measures. The results suggested the LPFS OR could be reliably coded, and the LPFS OR and LPFS SRA were significantly associated with outcome variables across psychodynamic and interpersonal paradigms. We discuss the implications of assessing personality dysfunction using the LPFS and the importance of expanding the research base for the AMPD model.