Ultraviolet B (UVB) radiation directly damages the skin, leading to disorders, increasing the demand for natural UV-absorbing compounds as alternatives to synthetic sunscreens. Mycosporine-like amino acids (MAAs), particularly mycosporine-glycine (M-Gly), are promising due to their antioxidant properties, low molecular weight, and high molar extinction coefficient. However, its application is limited by low natural abundance. In this study, we identified and recombined three genes (, , ) from to enable M-Gly production in BL21(DE3). M-Gly was purified via high performance liquid chromatography (HPLC) and characterized using UV, liquid chromatography-tandem mass spectrometry (LC-MS/MS), and nuclear magnetic resonance (NMR) spectroscopy. We explored its preventive and therapeutic effects on UVB-induced skin damage in HaCaT cells and mice. Western blot analysis suggests that M-Gly activates TGF-β/Smad and WNT/β-catenin signaling pathways to promote skin repair. This research provides an efficient synthesis platform for M-Gly and supports its potential use in therapeutics for skin photodamage.