<p>Ecosystem protection and food security are often viewed as competing goals, creating a critical policy dilemma for agricultural regions. Here we show that grassland restoration under China’s Grassland Ecological Compensation Policy significantly enhances maize yields through local climate regulation. Using a difference-in-differences design with county-level panel data, we find that restored grasslands reduce growing-season temperatures by 0.1 °C and increase precipitation by 11.48 mm, thereby mitigating heat and drought stress during critical reproductive stages. These changes extend the reproductive growing period by 0.93 days, increase yields by 7.76% (0.437 t ha⁻¹) and reduce crop shortfall risk by 25.9%. Yield gains alone offset more than 80% of programme costs within 5 years and the additional production could alleviate 10% of the maize import deficit in the Northern Spring Maize Region. Our findings highlight ecosystem restoration as a scalable strategy for achieving climate-resilient food security in regions similar to our study area.</p>