There has been increased attention to and emphasis on competency-based medical education and the transformation from highly supervised medical students towards independent, entrustable physicians. We explored how program directors (PDs) justify decisions about whether they would trust finishing Post Graduate Year 1 (PGY1) residents to care for the PD or a loved one. Using an end of year survey with validity evidence, we assessed PDs' responses (Yes, No, Not Sure) and written comments about this entrustment decision for USUHS medical students from graduating classes of 2013-2015 (PGY1). We performed a qualitative inductive content analysis to identify themes in how PDs justified their decisions as well as descriptive statistics and a contingency table analysis to examine associations between trust decisions and election to membership in Alpha Omega Alpha (AOA), or conversely, referral to the Student Promotions Committee (SPC) for remediation. Qualitative analyses revealed five themes related to this trust decision about medical residents: personal, interpersonal, knowledge, competence, and developmental. Neither AOA status, nor SPC referral status was significantly associated with the trust measure, overall, but positive trust decisions were significantly higher among those elected to AOA than in those who were not. Positive trust decisions were significantly associated with AOA status but negative trust decisions were not significantly associated with referral to the SPC. This study offers insights into what attributes may underpin trust decisions by PDs. Our findings suggest that PDs' frequent use of personal and interpersonal characteristics to justify trust decisions contrasts with the use of clinical and knowledge based assessments during undergraduate medical education (UME), and emphasize the importance of critical intrinsic abilities.