Calcareous soils constrain olive production through nutrient fixation and low biological activity. Integrated biochemical fertilization can enhance nutrient cycling and soil health. This study assessed the synergy between biofertilizers and chemical fertilizers on olive yield, oil quality, and soil properties in calcareous soils. A randomized complete block design with four treatments, that is, control (no fertilizer), chemical fertilizer, biofertilizer (mycorrhiza [200 spores/g, 500 g/tree, Bacillus subtilis/Pseudomonas spp. [10(8) colony-forming units (CFU)/mL, 250 mL/tree each], amino acids (5% w/v, 100 mL/tree), and integrated (biofertilizer + chemical fertilizer)-were implemented over three growing seasons (2021-2024). The biofertilizer treatment consisted of mycorrhizal inoculants (500 g/tree), Bacillus subtilis and Pseudomonas spp. (250 mL/tree each), and amino acids (100 mL/tree), applied via trench fertilization in winter/spring and foliar spraying in midsummer. The chemical fertilizer treatment included urea, potassium sulfate, triple superphosphate, iron chelate, and micronutrients, applied through trench fertilization, fertigation, or foliar spraying at critical growth stages (tree activation, fruit set, and fruit development), with dosages adjusted based on soil tests. The integrated treatment significantly enhanced olive yield by 26% compared to the control. Oil quality parameters also improved, with a 28% reduction in free fatty acids and a 67% increase in total polyphenols. The fatty acid profile was notably altered, featuring a 14% rise in oleic acid and a 18% decline in palmitic acid. Soil biological activity markedly increased under the integrated treatment, with Bacillus and Pseudomonas populations 2.6 times higher and soil enzyme activity 80% greater than the control. Additionally, the integrated approach improved soil health, increasing cation exchange capacity (CEC) by 92% and reducing the soil sodium-to-potassium (Na/K) ratio by 18%. These results demonstrate a clear synergistic effect between biofertilizers and chemical fertilizers in enhancing olive productivity, oil quality, and soil fertility. The study advocates for the integrated use of these fertilizers as a sustainable strategy for olive cultivation in calcareous soils of arid and semi-arid regions.