Many therapies have been shown to improve outcomes for patients with heart failure (HF) in controlled settings, but there are limited data available to inform best practices for hospital and post-discharge quality improvement initiatives. The CONNECT-HF study is a prospective, cluster-randomized trial of 161 hospitals in the United States with a 2×2 factorial design. The study is designed to assess the effect of a hospital and post-discharge quality improvement intervention compared with usual care (primary objective) on HF outcomes and quality-of-care, as well as to evaluate the effect of hospitals implementing a patient-level digital intervention compared with usual care (secondary objective). The hospital and post-discharge intervention includes audit and feedback on HF clinical process measures and outcomes for patients with HF with reduced ejection fraction (HFrEF) paired with education to sites and clinicians by a trained, nationally representative group of HF and quality improvement experts. The patient-level digital intervention is an optional ancillary study and includes a mobile application and behavioral tools that are intended to facilitate improved use of guideline-directed recommendations for self-monitoring and self-management of activity and medications for HFrEF. The effects of the interventions will be measured through an opportunity-based composite score on quality and time-to-first HF readmission or death among patients with HFrEF who present to study hospitals with acute HF and who consent to participate. The CONNECT-HF study is evaluating approaches for implementing HF guideline recommendations into practice and is one of the largest HF implementation science trials performed to date.