The generation of hydrogen in steam gasification can be improved by combining slow pyrolysis and steam gasification. The study investigates the effect of controlling parameters of slow pyrolysis-steam gasification on the generation of hydrogen. In the work, some native biomass wastes were first slow pyrolyzed, and then the generated chars were steam gasified to generate hydrogen. In slow pyrolysis, factors such as temperature, solid residence time, and particle size were optimized. In steam gasification, variables such as gasification temperature, residence time, steam-to-biomass ratio, catalysts, composition of catalysts, sorbents, composition of sorbents, and effective catalyst sorbent composition were optimized. Through slow pyrolysis, it was ensured that only high-quality char was available to steam gasification. It was found that the highest gasification temperature yielded the maximum amount of hydrogen. It was noticed that an optimal residence time and steam-to-biomass ratio was essential to generate the maximum amount of hydrogen. Among the selected catalysts, KCl generated the maximum amount of hydrogen. Of the selected sorbents, CaO offered the maximum amount of hydrogen. The combination of catalyst-sorbent (KCl-CaO) yielded the maximum amount of hydrogen. It was also observed that an optimal quantity of catalyst, sorbent, and catalyst sorbent was needed to generate the maximum amount of hydrogen.