Background: Sacubitril/Valsartan, an angiotensin receptor-neprilysin inhibitor (ARNI), represents a paradigm shift in the management of heart failure with reduced ejection fraction (HFrEF). Its robust efficacy in reducing mortality and hospitalization is well-established. However, as its use becomes ubiquitous, the recognition of rare and serious adverse events is paramount for optimizing patient safety. Case Presentation: A 57-year-old male with a complex medical history including type 2 diabetes, dyslipidemia, hypertension, chronic kidney disease (CKD stage 3a), and NYHA Class III HFrEF was initiated on Sacubitril/Valsartan 24/26 mg twice daily. Two weeks post-initiation, he presented with severe bilateral proximal myalgia, profound weakness, and classic tea-colored urine. Physical examination revealed significant muscle tenderness. Laboratory investigations were diagnostic for severe rhabdomyolysis, with a peak creatine kinase (CK) level of 18,540 U/L and concomitant acute kidney injury (AKI), evidenced by a rise in serum creatinine from a baseline of 1.4 mg/dL to 2.1 mg/dL. A meticulous workup excluded other common etiologies of rhabdomyolysis, including recent trauma, strenuous exertion, hypothyroidism, and illicit substance use. The patient had been on a stable, long-term dose of atorvastatin without prior incident. The Naranjo Adverse Drug Reaction Probability Scale score was 7, indicating a "probable" adverse drug reaction. Management involved immediate and permanent discontinuation of Sacubitril/Valsartan, aggressive intravenous fluid resuscitation, and close monitoring. A positive dechallenge was observed, with rapid symptomatic improvement and normalization of CK and renal function over the following week. Conclusion: This case provides compelling evidence for Sacubitril/Valsartan as a rare but potent precipitant of rhabdomyolysis, particularly in patients with predisposing factors such as CKD and concomitant statin use. It underscores the critical importance of clinician vigilance, pre-emptive patient education, and the prompt institution of management upon symptom recognition to prevent life-threatening complications like acute renal failure.