In this study, a new strategy to produce less entangled ultrahigh-molecular-weight polyethylene (UHMWPE) was proposed based on the exploitation of a nano-dispersed MgO/MgCl2/TiCl4 core-shell catalyst. Due to its poreless nature and the full dispersion of a single primary particle, the polymer chains grown from the catalyst surface can immediately crystallize without the disturbance of other polymer chains confined in pores. The melting characteristics of annealed polymer, the rheological properties, and the solid-state drawability of synthesized polymer clarified that the nano-dispersed catalysts enabled the production of less entangled UHMWPE even under an industrial condition. Featured with a tunable active-site density through the control of chlorination and the selection of a co-catalyst, more weakly entangled UHMWPE can be obtained at a reasonable activity.