Sudden cardiac arrest is a leading cause of death worldwide. Despite significant advances in resuscitation science since the initial use of external chest compressions in humans nearly 60 years ago, there continues to be wide variability in rates of successful resuscitation across communities. The American Heart Association (AHA) and European Resuscitation Council emphasise the importance of high-quality chest compressions as the foundation of resuscitation care. We review the physiological basis for the association between chest compression quality and clinical outcomes and the scientific basis for the AHA’s key metrics for high-quality cardiopulmonary resuscitation. Finally, we highlight that implementation of strategies that promote effective chest compressions can improve outcomes in all patients with cardiac arrest.