Punica granatum L. (pomegranate) is a nutritionally valuable fruit renowned for its rich phytochemical composition and broad spectrum of biological activities. Owing to its significant therapeutic potential, pomegranate has attracted considerable attention in the food, pharmaceutical, nutraceutical, and cosmetic industries. This review comprehensively summarizes the phytochemical profile, bioactive constituents, and health-promoting properties of different fruit components, including the arils, seeds, and peel. Pomegranate is particularly rich in polyphenolic compounds such as ellagitannins (punicalagin and punicic acid), ellagic acid, flavonoids, anthocyanins, and other phenolic metabolites that contribute substantially to its pharmacological activities. The arils constitute a valuable source of natural sugars, vitamins, minerals, and antioxidants, exhibiting potent antioxidant, antimicrobial, and prebiotic effects. Pomegranate seeds contain bioactive lipids, especially punicic acid, which have demonstrated anti-inflammatory, cardioprotective, antidiabetic, and anticancer properties. The peel, which represents a major agro-industrial by-product, is exceptionally rich in phenolic compounds and displays remarkable antioxidant, antimicrobial, antiviral, anti-inflammatory, and chemopreventive activities. Recent advances in extraction technologies, encapsulation approaches, and nano formulation strategies have significantly improved the stability, bioavailability, and therapeutic efficacy of pomegranate-derived bioactive compounds, thereby expanding their potential industrial and biomedical applications. Furthermore, valorising pomegranate processing by-products offers a sustainable approach for developing high-value functional ingredients and reducing environmental waste. Overall, pomegranate and its by-products represent promising natural resources for developing functional foods, nutraceuticals, cosmeceuticals, and novel therapeutic formulations. Future research should focus on optimizing extraction processes, elucidating molecular mechanisms of action, enhancing clinical translation, and exploring innovative applications of pomegranate-derived bioactives in health and disease management.