This study aimed to validate the health economic model for finerenone in the treatment of patients with heart failure (HF) and left ventricular ejection fraction (LVEF) ≥40% in the United Kingdom. A Markov model informed by the pivotal FINEARTS-HF trial compared finerenone + standard of care (SoC) to SoC alone. Cross-validation was performed on the results (life years [LYs] and quality adjusted life years [QALYs]) for the SoC arm against three models in HF with LVEF >40%. External validation compared cardiovascular (CV) mortality and the number of total HF events (hospitalisation for heart failure [HFF] and urgent heart failure visit [UHFV]) against FINEARTS-HF. The model estimated similar discounted outcomes to other models in HF (6.47 vs. 6.63–7.91 LYs and 4.78 vs. 4.63–5.27 QALYs). CV deaths (22 vs. 27) and UHFV events (60 vs. 61) avoided with finerenone were similar between the model and FINEARTS-HF. The broad estimated range of avoided HHF events (205–303 vs. 219 in FINEARTS-HF) was largely driven by baseline patient age. This comprehensive validation exercise demonstrated that the finerenone model accurately estimated observed clinical data and was well aligned in its projections with previous models assessing similar populations.