The widespread disposal of Irvingia gabonensis (ogbono) fruit waste in the Niger Delta poses environmental challenges, yet its potential as an organic soil amendment for crop production remains underexplored. This study investigated the effects of ogbono waste on the agro-morphological, physiological, soil physicochemical, and proximate parameters of maize (Zea mays L.) in Amassoma, Bayelsa State, Nigeria. The aim was to evaluate its suitability as a sustainable alternative to conventional organic fertilizer. The experiment was conducted using a randomized complete block design with three treatments: control, organic fertilizer (4t/ha), and ogbono waste compost (4t/ha) replicated three times over a 12-week period. Growth parameters were measured at Weeks 4, 8, and 12, while soil and proximate analyses followed standard AOAC and APHA procedures. Results showed that ogbono waste significantly (p < 0.05) enhanced mid-growth performance of maize, particularly at Week 8, where plant height reached 101.89 ± 43.11 cm in Sammaz 51 compared to 47.00 ± 18.18 cm in the control. Leaf area (5.78 ± 0.93 cm²), stem girth (5.22 ± 0.64 cm), and node number (9.44 ± 2.64) were also higher under ogbono treatment. Soil pH increased from 5.10 (T0) to 6.15 (T3), while nitrate rose from 12.4 to 22.8 mg kg⁻¹, indicating improved soil fertility. Proximate analysis showed high carbohydrate content (74.83–76.98%) and enhanced mineral levels, particularly zinc (26.34 ± 1.78 mg/100 g). The study concludes that ogbono waste compost significantly improves maize growth and soil nutrient status and is recommended as an eco-friendly organic amendment for sustainable maize production in humid tropical environments.