OBJECTIVE: A literature gap exists for interventions to decrease average length of stay (ALOS) for patients with psychiatric presentations at the emergency department (ED). Long ALOSs are often related to sequential assessments of patients with high suicide risk or patients awaiting an inpatient bed. Safety planning may provide opportunities for diverting patients to the community and for reducing ED ALOS. This study reports on the impact of a safety-planning approach based on the PROTECT (proactive detection) framework for suicide prevention. METHODS: A complex intervention (comprising leadership, governance, and innovation) was instrumental in embedding a new clinical culture of proactive detection and positive risk management through safety planning at Princess Alexandra Hospital in Brisbane, Queensland, Australia. Practice as usual continued at a comparator nonintervention site (NIS). In total, 24,515 psychiatric presentations over 24 months were grouped into monthly averages for key outcomes, providing a sample size of 24 at each site. A difference-in-differences analysis across sites, preintervention (January-November 2019) and postimplementation (December 2019-December 2020), was used to estimate the intervention's impact. RESULTS: ED ALOS for psychiatric presentations, patients with an ALOS >12 hours, patients with an ALOS >24 hours, and inpatient psychiatric admissions decreased significantly compared with NIS (p<0.01) pre- and postimplementation of the safety-planning intervention. CONCLUSIONS: Embedding a recovery-oriented culture of safety significantly reduced ED ALOS for psychiatric evaluations. Leadership, governance, and innovative practices that shift the focus of assessment and care from a mindset of risk prediction to one of prevention through collaborative safety planning as outlined in the PROTECT framework may have far-reaching benefits for patient care.