Ordered mesoporous carbons NCCR-41, NCCR-56, CMK-3, CMK-1, NCCR-11, and CMK-8 with varying pore size and pore dimensionality are prepared by adopting a nanocasting method employing sucrose as a carbon source and various ordered mesoporous silica templates. Systematic characterization of all the materials is done by various analytical and imaging techniques. Excess hydrogen sorption isotherms at 77 K and room temperature at high pressures are obtained using volumetric technique experiments. Correlation of the hydrogen sorption behavior with textural properties is discussed. Modeling of adsorption isotherms is done by converting excess adsorption to absolute adsorption isotherms using four different approaches. A nonlinear least-squares curve fitting technique is used to simultaneously estimate the volume of the adsorbed phase and absolute adsorption isotherm parameters for the modified Dubinin-Astakhov model.