IntroductionThe well-being of healthcare workers (HCWs) is critical to providing excellent care. Recent evidence concerns the well-being of emergency department (ED) HCWs in New Zealand, with high levels of burnout found in a 2020 survey. This threat to providing high-quality acute care warrants improvement interventions. The causes of burnout are complex and multifactorial, the solutions are not straightforward.Methods and analysisA prospective, multisite, before and after, mixed methods study assessing a multicomponent intervention, adaptable to local context, that targets three organisation levels (the individual, the group and the system levels) and meaningfully involves frontline HCWs may reduce HCW burnout and improve HCW well-being. Individual HCWs will choose from three individual-level psychological interventions and participate in those most appropriate for them. Local champions will decide which group-level intervention their ED will use. The system-level intervention will build capacity and capability for quality improvement (QI) with QI training and the establishment of a Quality Improvement Learning System. This system-level intervention has several important features that may ultimately empower HCWs to contribute to improving the quality of ED healthcare.We will enrol nine EDs, from which there will be at least 900 HCW participants. EDs will be enrolled in three waves from March 2023 to April 2024, with interventions taking place in each ED over 12 months.Methods of assessment will include baseline and repeat survey measures of burnout and well-being. Process evaluation at each ED will provide details of context, the intervention and the fidelity of the implementation.Ethics and disseminationEthics committee approval was provided, with locality approval at each site.Individual site feedback will be provided to each ED and executive leadership. Dissemination of findings will be through publication in peer-reviewed journals, presentation at national and international scientific meetings and through national healthcare quality bodies.Trial registration numberAustralia New Zealand Clinical Trials Registry (ACTRN12623000342617).