Background: Skin aging, a multifactorial process driven by intrinsic and extrinsic factors, results in diminished hydration, elasticity, and increased wrinkle formation. Yeast extract, particularly from Saccharomyces cerevisiae (S. cerevisiae), is rich in bioactive compounds with potential anti-aging properties, but its effect via oral administration remains underexplored. Objective: To evaluate the anti-aging efficacy of glutathione-enriched S. cerevisiae yeast extract in a photoaging-induced mouse model and human skin cell lines, including fibroblasts and keratinocytes, focusing on its molecular mechanisms. Methods: In vitro studies were conducted using human dermal fibroblasts and keratinocytes to assess antioxidant activities of yeast extract (SOD and GPx), inflammatory markers (IL-1 beta, IL-6, TNF-alpha, and COX-2), and effects on aging-associated factors such as collagen, elastin, hyaluronic acid production and matrix metalloproteinase (MMP), collagenase, elastase, hyaluronidase activities. For in vivo studies, SKH-1 hairless mice were exposed to UVB irradiation to induce photoaging and orally administered yeast extract at various doses. Skin improvements were evaluated through measurements of hydration, trans-epidermal water loss (TEWL), elasticity, collagen fiber density, roughness, and epidermal thickness. Results: The yeast extract exhibited significant anti-aging effects in both in vitro and in vivo models. In vitro, it upregulated collagen and elastin synthesis, enhanced hyaluronic acid content, promoted antioxidant enzymes, and lessened inflammatory markers. Additionally, key dermal degradation factors, including MMP, elastase, collagenase, and hyaluronidase, were significantly downregulated. In vivo, oral administration improved skin hydration, TEWL, elasticity, and collagen fiber density, while visibly reducing wrinkle depth and roughness. Histological analysis further confirmed decreased epidermal thickness and increased collagen deposition, highlighting the extract's potential in skin rejuvenation. Conclusions: Glutathione-enriched S. cerevisiae yeast extract showed substantial promise as a multifunctional anti-aging agent. It enhanced skin hydration, reduced oxidative stress, mitigated inflammation, and improved structural integrity, offering a comprehensive approach to combat skin aging.