<p>This study investigates the synergistic effects of deposition sequence and arc oscillation on the interface and properties of wire arc additively manufactured 2319/5356 dissimilar aluminum alloys. Addressing challenges such as poor bonding and inconsistent performance, a Box-Behnken design with response surface methodology was employed to optimize arc oscillation parameters (frequency, amplitude, and torch angle) targeting hardness and porosity. Results indicate that the 2319-on-5356 deposition sequence yields superior performance, exhibiting excellent surface flatness, sufficient interfacial element diffusion, and the formation of strengthening phases like Al₂Cu, Al₂CuMg, and Al₃Mg₂. Under the optimal parameters (amplitude 6.19 mm, frequency 4.0 Hz, angle 82.2°), experimental validation confirmed that the component achieved a low actual porosity of 0.81% and an average hardness of 89.3 HV_0.2, strongly verifying the accuracy of the established Box-Behnken model. Compared to the process without oscillation, the optimized strategy refined the average grain size to 21.23 μm and increased tensile strength by 29.11% to 216.46 MPa. Additionally, corrosion uniformity was significantly improved. These findings demonstrate that coordinated control of deposition sequence and arc oscillation effectively mitigates defects and enhances the mechanical properties of heterogeneous aluminum components.</p>