In this study, we fabricated porous polyketone (PK) support membranes with high pressure resistance and low structural parameter (S) by surface modification with aromatic compounds for osmotically driven membrane process applications. The effects of surface modification of PK using aromatic compounds on the membrane structure, mechanical properties, and membrane performance were investigated. Based on an estimation of the affinity between PK and aromatic compounds using Hansen solubility parameters and mechanical properties, m-phenylenediamine (MPD) was selected as an appropriate chemical modifier for PK membranes. The PK support membranes modified with MPD (PK-MPD) had a dense structure on the bottom side. The thickness and porosity of the PK membranes were changed by the treatment temperature. As a result, polyamide (PA)/PK-MPD thin film composite membranes showed superior pressure resistance in reverse osmosis. PA/PK-MPD modified at 110 °C possessed the highest pressure resistance of 21 bar, which was 3.5 times higher than that of the PA/untreated PK membrane, while maintaining a high water flux of 19.4 L m−2 h−1 in FO. This performance overcame the trade-off relationships between pressure resistance and FO flux and between pressure resistance and S value.