White button mushroom (Agaricus bisporus) cultivation is very sensitive to environmental changes; thus, this calls for a tight monitoring of environmental conditions, which in conventional practice is labor-intensive, inconsistent, and prone to human error. In Zimbabwe, mushroom growers predominantly rely on manual climate control, which has reduced yields, increased operational costs, and enhanced crop losses. The present study is, therefore, aimed at the design and implementation of an IoT Real-Time Monitoring and Automated Control System in enhancing the growth of white button mushrooms in Zimbabwe. The system comprises an ESP32 microcontroller interfaced with DHT22 temperature–humidity sensors, 12 V DC ventilation fans, a humidifier, relay modules, and an LCD for on-site monitoring. The complementary design of a mobile application using React allows for IoT cloud connectivity, enabling remote real-time viewing of data. Prototype testing showed that the system could measure environmental parameters like temperature, humidity, and ventilation accurately and was able to automatically actuate them to maintain optimum growing conditions within the crop canopy (22–25 °C and 70–90% humidity). Experimental results revealed that with deviations, the prototype responded effectively by turning on ventilation at 26 °C and initiating correction in humidity at 69%. The results confirm that the system could improve crop uniformity, reduce labor use, and enhance efficiency of production.