(1) Background: this study addresses the lack of comprehensive research on outcomes in octogenarians undergoing cardiac surgery for multivalvular disease, emphasizing the need for a critical examination of the intervention's overall worth in this aging population. (2) Methods: By analyzing short-term and mid-term data from 101 consecutive octogenarian patients undergoing multivalve surgery, the study identifies predictors for in-hospital and one-year mortality. (3) Results: In-hospital mortality increased fourfold with the occurrence of at least one postoperative complication. Octogenarians undergoing multivalve surgery experienced an in-hospital mortality rate of 13.9% and an overall one-year mortality rate of 43.8%. Postoperative delirium was identified as an independent risk factor, contributing to elevated risks of both in-hospital and one-year mortality. Prolonged surgical procedure time emerged as an independent risk factor associated with increased in-hospital mortality. Continuous veno-venous hemodialysis showed an independent impact on in-hospital mortality. Both re-intubation and the transfusion of packed red blood cells were identified as independent risk factors for one-year mortality. (4) Conclusions: This study urges a critical examination of the justification for multivalve surgeries in high-risk elderly patients, emphasizing a paradigm shift. It advocates for interdisciplinary collaboration and innovative strategies, such as staged hybrid procedures, to improve therapeutic approaches for this challenging patient group to achieve a better therapeutic outcome for these patients.