Background: This study investigates the hypolipidemic effects of a mixed extract of Salvia miltiorrhiza and Paeonia lactiflora (USCP119) in HFD-fed hamsters and in vitro cellular models. Methods: Over an 8-week period, HFD-fed hamsters were assigned to one of six groups: normal diet, HFD control, HFD with 50 mg/kg USCP119, HFD with 100 mg/kg USCP119, HFD with 50 mg/kg USCP119 twice daily (BID), and HFD with omega-3 fatty acids. Key outcomes assessed included body weight, serum triglycerides (TG), total cholesterol (TC), liver weight, hepatic TG levels, and epididymal fat. In cellular models, the impact of USCP119 on lipid accumulation and adipogenic markers was evaluated. Results: USCP119 treatment at 50 mg/kg BID resulted in the lowest weight gain (15.5%) and the most significant reductions in serum TG and hepatic TG levels compared to the HFD control. The 100 mg/kg dose also led to substantial reductions in serum TG and TC levels and notable decreases in low-density lipoprotein cholesterol. USCP119 at 50 mg/kg once daily reduced TG and TC levels but was less effective than the higher doses. In cellular models, USCP119 was non-toxic up to 400 µg/mL and effectively reduced lipid accumulation, modulated adipogenic markers, and enhanced AMPK signaling, improving lipid metabolism and insulin sensitivity. Conclusions: All USCP119 treatments demonstrated effectiveness in managing hyperlipidemia and related metabolic disorders, with variations in impact depending on the dosage. The ability of USCP119 to reduce fat accumulation, improve lipid profiles, and enhance insulin sensitivity highlights its potential as a valuable dietary supplement for addressing high-fat diet-induced hyperlipidemia and metabolic disturbances.