Due to increasing global climate change problems to biota, salinity has been recognized as a realistic hazard critically affects the sustain agri-food production and crop quality in many regions of the world. Nanotechnology as an innovative approach can effectively improve plant performance under risky conditions such as salinity. Taking in consideration the ameliorative role of nanoparticles such as calcium nanoparticles (Ca-NPs) in enhancing plant growth and tolerance against various abiotic stresses, the present study was undertaken to illuminate the powerful effect and the underlying mechanism of soil-applied Ca-NPs (20 mM) in preventing salt damage at saline conditions (NaCl at 50, 100 and 200 mM) in tomato. Data revealed that NaCl drastically imposed the morphological parameters, primary and secondary metabolism, photosynthesis pigment content, hydrogen peroxide and lipid peroxidation levels, antioxidant enzyme activities, mineral contents, and protein patterns. In contrast, the supplementation of exogenous Ca-NPs modified salinity toxicity effects by improving the survival, growth parameters, anabolic (soluble ions and osmolytes) and defense mechanisms (enzymatic and nonenzymatic antioxidants). Interestingly, under lethal salinity level (200 mM), Ca-NPs was capable of suppressing the excessive damage effect of salinity by up-regulating the performance of the plants when these plants were completely dead in the absence of Ca-NPs. The descriptive cluster analysis separated treatments and characteristics into 3 to elucidate negative and positive correlations.  Moreover, Ca-NPs was more efficient than CaCl₂ in eliciting salt tolerance under all investigated NaCl levels. Therefore, all these findings together conclude that Ca-NPs have a positive role in motivating resilience strategies in tomato plants toward salt stress via lessening the ROS overproduction, stimulating enzymatic antioxidants, promoting osmolytes accumulation, and renovating protein profile under mild and severe salinity levels.