The edible morel mushroom (Morchella esculenta) was tested as a natural filter for industrial wastewater, targeting the textile dye Eriochrome Black T. The mushroom biomass removed up to 88% of the dye at pH 5.0, with efficiency increasing as more material was added. It could be regenerated and reused for at least four cycles, making it a low-cost and sustainable biosorbent. Advanced analyses (FTIR, SEM, molecular simulations) confirmed strong binding between dye molecules and the mushroom’s surface, pointing to an eco-friendly solution for dye pollution.