Porous hydrophobic/oleophilic materials have shown great potential for oil spill remediation applications. However, in order to increase the oil removal throughput, large pore size and high void fraction are required, which compromises the selectivity of oil/water separation since water may pass through the macropore channels along with oil. In this work, we have circumvented this challenge by elaborately designing hierarchically porous polymers through leaching the sacrificial poly(styrene-ethylene/butylene-styrene) (SEBS) and polylactide (PLA) phases in the tricontinuous ternary polypropylene (PP)/SEBS/PLA blend system. The hierarchically porous structures (with a pore diameter of 0.1-2.2 and 8.7-82 μm at two scales respectively) of PP are controlled by interfacial properties and phase coarsening during thermal annealing. As compared to unimodal pores, the incorporation of the secondary smaller pores significantly enhances the oil removal throughput by 500% without increasing the diameter of the primary pores, which, in turn, prevents compromising the oil/water separation selectivity.