The demand has grown in many fields for materials that are eco-friendly and sustainably developed. In this study, several formulations of novel wood fiber reinforced ultra-high-density fiberboards (UHDFs) using resol-type phenolic resin (RTPR) as binders were manufactured for application in decorative building facades. The inﬂuences of the various formulations on water resistance and the mechanical, thermal, and fire-resistant properties were systematically examined. All formulations of the UHDFs exhibited better water resistance, internal bonding, and fire resistance as the RTPR content and density increased. To better evaluate mechanical properties, the microstructure of the UHDFs was observed using scanning electron microscopy. After optimization of hot-pressing conditions, UHDFs with excellent mechanical properties of approximately 7.2 GPa, 85.9 MPa, and 5.4 MPa for bending modulus, bending strength, and internal bonding, respectively, were achieved. Good water and flame resistance were also achieved, which makes these materials competitive with other commercial products.