Biomass-derived levulinic acid (LA) and its esters are currently envisaged as versatile, renewable platform chemicals. In this study, cellulosic pulp derived from the cooking of lignocellulosic biomass with active oxygen and solid alkali was employed as raw material for the formation of LA or ethyl levulinate (EL). This pretreatment process is highly effective for the delignification and deconstruction of lignocellulose matrix, making a facile degradation of the resulting cellulosic pulp to LA or EL. At this point, the acid-catalyzed hydrolysis or ethanolysis of cellulosic pulp was optimized by response surface methodology (RSM), offering desirable LA yield of 65.3% or EL yield of 62.7%, which is significantly higher than those obtained from raw biomass. More importantly, coking behavior on the inwall of the reactor was eliminated during the hydrolysis or ethanolysis of cellulosic pulp, which is one of the top challenges for the acid-catalyzed conversion of biomass in an industrial scale.