Chromolaena odorata is a fast-spreading invasive plant species that poses a serious threat to agricultural ecosystems, particularly in sub-Saharan Africa. Despite its reputation as a harmful weed, there has recently been an increase in interest in its potential use as an organic soil improver. This study evaluates the impact of C. odorata biomass on soil physicochemical properties, specifically pH and moisture content, as well as on the agronomic performance of maize (Zea mays). The experiment was conducted in Zépréguhé, in the Haut Sassandra region of central-western Côte d’Ivoire, using a randomised complete block design. Four treatments were tested: C. odorata biomass alone; C. odorata combined with a 170 kg/ha mineral fertiliser (NPK 15-15-15); mineral fertiliser alone; and an untreated control. A single maize variety (LG-501) was used to ensure consistency across the treatments. The agronomic parameters measured included plant height, the number of leaves, the stem base diameter and the yields of ears and grain. Soil pH and moisture were also assessed. The results showed that the treatments involving C. odorata significantly enhanced plant growth and increased soil moisture, while slightly neutralising soil acidity. Applying C. odorata alone produced the highest yields (10.74 t/ha for ears and 7.62 t/ha for grain), outperforming the mineral fertiliser treatment and the control. The combination treatment also yielded good results, albeit slightly lower. These results suggest that C. odorata biomass could be used as an effective, inexpensive alternative to or addition to synthetic fertilisers, thereby promoting soil health and sustainable maize production in tropical agroecosystems.