Plant-derived foods are rich in bioactive compounds with notable therapeutic potential. Plantain (Musa paradisiaca L.) is widely cultivated and traditionally used in managing inflammation and diabetes. This study investigated the cardioprotective effects of the ethanol extract of a polyphenol-rich unripe (green) M. paradisiaca peel in a rat model of type 2 diabetes. Bioactive compounds were identified using GC-FID, followed by molecular docking with relevant protein targets. Type 2 diabetes was induced using a high-fat diet (12 weeks) and streptozotocin (35 mg/kg). Diabetic rats were treated with 200 and 400 mg/kg extract for 30 days. HFD/STZ-induced diabetic rats showed elevated fasting blood and serum glucose, dyslipidemia, increased creatine kinase-MB, lactate dehydrogenase, interleukin-6, C-reactive protein, tumor necrosis factor-α, and troponin I, all significantly reduced by the extract. Reduced adiponectin levels were significantly improved (p < 0.05), alongside the attenuation of oxidative stress. Histology revealed reduced myocyte degeneration and inflammatory cell infiltration with evidence of regeneration. Molecular docking suggested that polyphenols contributed to the observed antidiabetic activity. In conclusion, the ethanol extract of green plantain peels possesses antihyperglycemic, antidyslipidemic, anti-inflammatory, antioxidant, and cardioprotective properties.