Rate control plays a fundamental role in the management of atrial fibrillation (AF), but the optimal target of resting heart rate (RHR) for reducing mortality remains uncertain. This study used longitudinal follow-up RHR data to evaluate the relation between RHR and all-cause mortality. Data from the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study were retrospectively analyzed. The association between RHR and mortality was longitudinally analyzed using mean RHR (mRHR) and trajectory patterns, where the Cox proportional hazards model and group-based trajectory model were used. A total of 3,921 patients (mean age, 69.47 ± 8.09 years) with AF were included in our study. A total of 578 deaths were recorded during a median follow-up of 3.4 years. Cox regression analyses showed an mRHR ≥80 bpm was associated with an increased risk of mortality (adjusted hazard ratio: 2.01, 95% confidence interval 1.59 to 2.55). Consistent association was found in the subgroup analyses. The Kaplan-Meier analysis showed notably reduced survival probabilities for patients with mRHR ≥80 bpm. Patients were classified into 4 stable trajectories based on RHR during follow-up, with the classes >70 bpm associated with an elevated risk of mortality. In conclusion, longitudinally measured RHR ≥80 bpm was associated with an increased risk of mortality in patients with AF.