Functional and synbiotic beverages are gaining rapid consumer acceptance owing to their combined probiotic and prebiotic health benefits, yet systematic, enzyme-assisted formulation of fruit-based synbiotic smoothies remains limited, particularly for regionally important cultivars such as Kesar mango (Mangifera indica L.). The present study aimed to develop and characterize a synbiotic Kesar mango smoothie through enzymatic liquefaction of mango pulp, incorporation of probiotic yogurt and inulin, and evaluation of its physicochemical, microbiological, sensory and storage attributes. Enzymatic liquefaction of Kesar mango pulp was optimized using a Central Composite Design (pectinase 100-150 IU, cellulase 2-8 IU, temperature 30-45 °C, time 5-15 min) under Response Surface Methodology (RSM), maximizing juice yield and overall acceptability, the optimum conditions (112.50 IU pectinase, 6.50 IU cellulase, 41.25 °C, 11.05 min) gave a validated juice yield of 83.71% and an acceptability score of 7.85 (9-point hedonic scale). The smoothie formulation (mango juice 20-40 g, yogurt 50-75 g, sugar 5-15 g, inulin 3% and xanthan gum 0.2% fixed) was optimized using a D-optimal mixture design, yielding an optimum formulation of 40 g mango juice, 50 g yogurt and 10 g sugar with a predicted acceptability of 8.35 (validated: 8.33). The optimized smoothie contained 75.95% moisture, 1.47% protein, 1.78% fat, 19.15% carbohydrate, 24.50 °Bx TSS, pH 4.46, 0.81% titratable acidity, 47.90% antioxidant activity and 240.60 mg GAE/100 mL total phenolics, with viable Lactobacillus acidophilus and Bifidobacterium animalis counts of 8.20 and 8.01 log CFU/mL, respectively, and no detectable yeast, mould or coliforms. During 27 days of refrigerated storage (5 ± 2 °C), overall acceptability declined from 8.33 to 5.62 while probiotic counts remained above the therapeutic minimum of 6 log CFU/mL throughout, indicating a sensorially acceptable and microbiologically safe shelf life of approximately three weeks. These findings demonstrate the feasibility of Kesar mango as a base for a nutritionally enriched, functionally active dairy-fruit beverage with commercial potential.