Harnessing their excellent physical attributes, two-dimensional nanostructures have gained prominences as reinforcements in polymer nanocomposites. Given the intricate structure of nanofillers and the varied interfacial connections, in-depth understanding of the strengthening mechanisms becomes pivotal for optimizing nanocomposite design. By varying the GO's morphology, a notable divergence of approximately 30% is evident in the interfacial shear strength. This divergence is attributed to the mechanical interlocking effect instigated by the presence of -O- and -OH functional groups. Functionalizing with groups like -CH3-CH2-NH2 (-Ethylamine) and -(HOCH2)3CNH2 (-TRIS) enhances the mass density of PE polymers at the interphase, which changes the interface sliding (low-density interphase) to the cohesive sliding during the pull-out process. As a result, the maximum interfacial shear strength (204–223 MPa) of these two samples is much larger than that of the pristine GO/PE (149–151 MPa), and even comparable with the pure PE's tensile strength. Intriguingly, shorter or highly flexible functional group exhibit a comparatively weaker influence on the interfacial shear strength. Moreover, as the sliding surface shifts toward the cohesive zone, diminishing sample thickness (less than 60 Å) generally corresponds to augmented interfacial shear strength due to the boundary confinement effect. In summary, this work offers a comprehensively elucidation of GO/PE pull-out behavior, facilitating the design of nanocomposites with exceptional mechanical performance.