Button mushroom (Agaricus bisporus) cultivation in India remains highly seasonal, with farmers facing yield losses and quality decline in warmer months. To address these limitations, we evaluated Mushroom Kothi, a low-cost IoT-enabled cultivation chamber, across three agro-climatic zones and multiple growing seasons. The system integrates temperature, humidity, and CO₂ sensors with automated misting and ventilation, ensuring a stable microclimate independent of external fluctuations. Comparative trials between Mushroom Kothi units and farmer-managed controls (n = 30 per season) revealed that the device extended productive cultivation by up to two additional months beyond the conventional season. Yield improvements averaged 20%, with water-use efficiency gains of 35–40% and crop loss reduction of nearly one-third. Post-harvest shelf life improved by 1–2 days due to reduced disease incidence and more uniform fruiting. Beyond production, operational data showed fewer manual interventions and lower labor time, confirming usability for smallholders with limited resources. Resource-use metrics (liters of water and watt-hours per kilogram yield) confirmed the significantly higher efficiency in Mushroom Kothi systems, supporting sustainable intensification goals. These results highlight the potential of digitally assisted chambers to provide stable year-round income, reduce environmental footprint, and strengthen smallholder resilience. Future research will extend the trials to additional regions and test integration with renewable energy to further improve sustainability.