This study aimed to assess the feasibility of chestnut inner shell powder (CISP) as a functional upcycled ingredient in ganache chocolate and to evaluate changes in its quality characteristics according to different supplementation levels. Ganache samples were formulated with 0% (CON), 3% (CISP3), 6% (CISP6), 9% (CISP9), 12% (CISP12), and 15% (CISP15) CISP, and analyzed for physicochemical properties, color, texture profile, and consumer acceptance. As the supplementation level increased, significant changes were observed in both physicochemical and sensory attributes. Moisture content increased, whereas pH decreased. Hunter color values L (lightness) and a (redness) declined, resulting in a darker appearance with a more pronounced green hue. Texture Profile Analysis indicated decreases in hardness, adhesiveness, gumminess, and chewiness, while cohesiveness and springiness increased at higher levels. Consumer evaluation showed that CISP3 achieved the highest scores for appearance, flavor, texture, and overall acceptability. These findings suggest that 3% CISP offers the most favorable balance of physicochemical and sensory qualities in ganache chocolate. The study highlights the potential of chestnut inner shell powder as a value-added upcycled ingredient and recommends further investigation into storage stability and functional enhancement for future commercial applications.