Lentinus swartzii, belonging to Basidiomycota, is one of the unrecorded and un-utilized naturally-occurring mushrooms in the Philippines. With the intention to realize the full potential of this wild mushroom, the present work highlights the successful rescue, domestication, optimization of culture conditions (culture media, pH, and physical factors) for mycelial growth, and evaluation of the fruiting body production on formulated substrate. The mycelia favorably grew on coconut water gulaman (CWG), potato sucrose gulaman (PSG), and potato dextrose agar. However, for practical and economic reasons, CWG was the basal medium used in the evaluation of pH and physical factors. The better-quality mycelial growth was obtained when cultured on CWG at pH 6, and incubated in the dark, 30°C, under sealed conditions. Both rice seeds and cracked corn were the most suitable materials for grain spawn production. Among substrate formulations, 7:3 ratio of rice straw and sawdust produced the highest mean weight of fruiting bodies (37.02 g per bag) and biological efficiency (7.40%). Enriched cultivation of this mushroom by adding nutritious supplements in the substrate must be done in further studies.