Resolving severe interface reactions and unclear interfacial bonding mechanisms in graphene/Ti matrix composites is imperative for their widespread application in advanced technological domains such as aerospace, defense, and medicine. This study amalgamates density functional theory calculations with experimental investigations to study the interfacial interactive behavior between Ti and graphene with pristine and defective structures. Calculative results reveal the presence of weak interactions between pristine graphene and Ti, which differs from the chemical reaction between defective graphene and Ti. The interfacial bonding characteristics of Ag-Cu-Ti eutectic foils on a pure Cu substrate (P-Cup), Cu substrate with pristine graphene (G-Cup), and Cu substrate with defective graphene (VFG-Cup) were studied through the sessile drop method at a moderate temperature of 880 °C (lower than the melting point of Ti). The Ag-Cu-Ti filler displayed sound wettability on P-Cup, G-Cup, and VFG-Cup. Specifically, the contact angles were approximately 2°, around 6°, and less than 1°, respectively. By observing the interfacial microstructure, pristine graphene is proved to be preserved, indicating that it impedes self-erosion as well as the Cu substrate by the active Ag-Cu-Ti filler. The defect-rich graphene behaves the opposite, aligning with the findings of the density functional theory calculations. This work holds significant potential in guiding the design of graphene-reinforced metal matrix composites.