In a quest to meet the rising demand for nutrient-rich products, this study delves into the realm of innovative bars enriched with Aronia melanocarpa by-product powder. By repurposing waste material from fruit pressing, the research unveils a sustainable approach to enhancing the health profile of food products. Two variants of bars were used: one as a control and the other enriched with freeze-dried aronia by-product powder. Both bars had similar nutrient content, containing approximately 10% fibre, 12.20% protein, 20.51% fat, and 429–430 kcal calories. The investigation showcases a remarkable 61% increase in antioxidant activity in bars enriched with freeze-dried aronia powder compared to traditional bars. In vitro digestion tests demonstrated enhanced nutrient release in aronia powder-enriched bars. Moreover, a 70-day storage analysis demonstrated the microbiological stability of the bars, which is essential for their commercial viability (final total viable cell count 4.41 log10 CFU/g). Also, total fungi-yeast and moulds increased to 4.17 ± 0.131 log10 CFU/g for aronia bars and to 3.91 ± 0.107 log10 CFU/g for control bars after 70 days of storage. This collaborative research effort not only sheds light on the nutritional and physico–chemical characteristics of the innovative bars but also propels the development of functional food products with heightened antioxidant content and bioactive compounds.