BACKGROUND: The rate of patients who leave without being seen (LWBS) from an emergency department (ED) is a common measurement of quality, operational efficiency, and patient satisfaction. We hypothesized that adding a nonclinical staff role, guest service ambassadors (GSA), to the ED waiting room would decrease LWBS rates and reduce existing differences by race, ethnicity, sex, and primary language for ED patients. METHODS: We conducted an observational cohort study at a quaternary care academic ED in the Midwestern United States with approximately 60,000 annual visits between April and December 2022. GSAs were trained to guide patients and visitors through the check-in process and help manage the waiting room. LWBS rates were compared between pre- and postimplementation periods using logistic regression. Using two-sample proportion tests, subgroup analyses were performed to assess differences according to race, ethnicity, sex, and primary language. RESULTS: We analyzed 50,507 ED visits including 9798 during periods of GSA coverage. GSA presence was associated with a reduction in LWBS rate from 3.4% to 2.0% (absolute risk reduction [ARR] of 1.4%, χ CONCLUSIONS: Although some disparities remain, our study suggests that GSAs may provide an effective strategy to reduce the overall LWBS rate and reduce disparities across diverse demographic groups including BIPOC and female patients.