Salinization induced by salt stress is a critical environmental factor, and limits the expansion of agricultural areas and population distribution in continental regions, including Saudi Arabia. Common beans, a vital source of protein, energy, and dietary fibers, are negatively affected by salt stress. In this research, the endophytic fungus Cladosporium halotolerans was utilized to remediate saline soils and enhance common bean growth and resilience. The results of this study demonstrated that soil treatment with C. halotolerans enhances the soil properties by decreasing soil pH and increasing soil organic matter content under saline conditions. Inoculation by C. halotolerans also significantly improved plant growth parameters, induced systemic resistance to salinity, and increased the levels of chlorophyll b and carotenoids. Fungal inoculation also causes stress relief as indicated by reducing malondialdehyde concentration by 27.4% lower than stressed plants. Microscopic images revealed the active association and colonization of C. halotolerans within the roots of the Phaseolus vulgaris both under control and saline conditions. Therefore, utilizing endophytic fungi C. halotolerans for saline soil remediation appears to be a promising alternative in plant treatments, highlighting their potential as valuable resources for both research and commercial applications under salinity stress.