Aerogel sulfated ZrO₂–SiO₂ mixed oxide solid acid catalyst was prepared by sol–gel method followed by supercritical drying (SCD) in n-propanol solvent, which resulted into higher surface area (170 m²/g), pore volume (0.31 cm³/g) and pore diameter (7.2 nm) having ordered mesoporous structure as well as more number of Brönsted and Lewis acid sites available on larger surface area. The catalyst exhibited 91 % yield of methyl stearate at 60 °C in 7 h, which increased from 71 to 91 % with an increase in the Zr to Si ratio from 1:2 to 2:1 due to increase in acid site concentration. The reaction followed pseudo-first order kinetics under the optimized reaction conditions with a reaction rate of 1.15 mmol h⁻¹, rate constant of 2.7 × 10⁻¹ h⁻¹ and turn over frequency of 9.68 h⁻¹. The catalyst displayed higher activity (91 %) compared to ion exchange resins (44–68 %), Nafion (58 %), acid clay (61 %) and pure sulfated zirconia (78 %), and was slightly lower as compared to H₂SO₄ (97 %). The study clearly reveals the improved structural, textural and acidic properties of ZrO₂–SiO₂ mixed oxide aerogel prepared via SCD technique.