Amid growing global challenges such as population growth, climate change, and limited natural resources, the need for sustainable farming systems to ensure food security and environmental conservation has become increasingly critical. This study – conducted in the forest zones of Ghana during the major and minor cropping seasons of 2023 – evaluates the effects of integrating Cajanus cajan (also known as pigeon pea), a leguminous shrub, into a maize cropping system. This maize–pigeon pea (MPP) intercropping approach is part of an innovative integrated soil fertility management strategy aimed at improving maize yield, farm profitability, and climate resilience of smallholder farmers. A split-plot experimental design was employed, with the cropping systems – MPP intercrop and sole maize – as main plots, and varying recommended inorganic fertilizer (full rate [FR], half rate [HR], and a no-fertilizer control) as subplots. The findings revealed a significant association between the MPP intercropping system and the rate of inorganic fertilizer application on maize growth and yield, with improved and comparable maize productivity observed when either the HR or FR fertilizer was applied. This suggests that integrating pigeon peas and their biomass could reduce the recommended fertilizer rate by half, thereby enhancing farmers’ income and profitability while promoting sustainable maize production amid climate change. Future research should explore long-term soil fertility dynamics and broader agroecological applications.