This study explores the incorporation of Ganoderma lucidum (Curtis) P. Karst. (Reishi mushroom) into wheat bread to develop a functional food with enhanced nutritional value. Reishi powder was added to bread formulations at levels of 3%, 6%, 9%, and 12% to assess its effects on physicochemical, nutritional, and sensory properties. The 12% Reishi supplementation resulted in a twofold increase in total dietary fibre (from 7.21 g to 17.08 g per 100 g dry matter) and significant (p < 0.05) elevations in mineral content, particularly calcium (68%), iron (32%), and manganese (61.9%). Carbohydrate content decreased markedly by 27%, contributing to a 19.33% reduction in caloric value. Reishi addition improved bread yield and reduced baking losses, enhancing production efficiency. However, higher Reishi levels negatively impacted bread volume, possibly due to interference with gluten network formation. An increase in crumb moisture was observed, contributing to extended freshness. Sensory evaluation revealed that loaves of bread containing up to 6% Reishi were acceptable to consumers, whereas higher levels detrimentally affected flavour and aroma. Therefore, Reishi-enriched bread, particularly with 6% supplementation, presents a promising functional alternative to conventional wheat bread, optimising nutritional benefits while maintaining consumer acceptability.