This study investigates the physicochemical and phytochemical profile of Curcuma caesia Roxb. (black turmeric), a medicinal plant recognized for its significant therapeutic and cosmetic potential. Rhizome samples were subjected to solvent extraction, followed by Gas Chromatography–Mass Spectrometry (GC-MS) and Fourier Transform Infrared Spectroscopy (FTIR) to characterize bioactive constituents and functional groups. GC-MS analysis identified α-santalol (46.90%), ar-turmerone (10.38%), and retinal (10.72%) as the major components, highlighting the extract’s strong antioxidant and anti-inflammatory potential. FTIR spectra confirmed the presence of characteristic functional groups, including N–H, O–H, C=C, and C–O, consistent with phenolic, terpenoid, and aromatic compounds. Physicochemical evaluation demonstrated a pH of 6.60 and moisture content of 12.52%, indicating suitability for topical formulation stability. Leveraging the richness of these bioactive compounds, three cosmetic formulation prototypes were developed and evaluated to represent distinct cosmeceutical applications. An anti-aging serum was formulated to deliver concentrated phytochemicals aimed at enhancing skin rejuvenation, improving collagen integrity, and reducing visible signs of aging. A photoprotective day cream was designed to provide daily defense against UV-induced oxidative stress while maintaining skin hydration and reinforcing the epidermal barrier. Additionally, a herbal face mask was developed as a rinse-off formulation to promote deep cleansing, antioxidant activity, and overall skin revitalization through synergistic herbal actives. While the findings underscore C. caesia as a promising candidate for standardized cosmeceutical and medicinal use, further investigations are warranted. Future research should focus on nanoencapsulation strategies for enhanced delivery, detailed bioavailability studies, comprehensive toxicity screening, and clinical validation to substantiate safety and efficacy for commercial applications.