The inoculation of Chrysanthemum plants with B. licheniformis SA03 ameliorated the detrimental impacts caused by saline–alkaline stress by enhancement of the ABA levels. Soil inoculation sufficiently activated a series of adaptive mechanisms such as increased antioxidant enzymatic activities, enhanced Fe acquisition, and decreased Na+ accumulation in host plants, which were in correlation with the actions of NO. The findings confirmed the roles of SA03 in assisting host plants to saline–alkaline stress and its use as a potential strategy in sustainable agriculture.