This study explores the influence of various Metal Inert Gas (MIG) brazing modes on critical factors such as the process stability, bead morphology, microstructure and mechanical performance of brazed lap joints of dual-phase (DP600) steel. Through systematic analysis of voltage/current signals and deposition characteristics, this research reveals how variations in heat input impact material flow and wettability during the brazing process. A higher heat input has been found to enhance wettability and improve joint strength, yet it can lead to a reduction in the cross-sectional area, ultimately affecting resistance to failure. Conversely, lower heat inputs contribute to more stable deposition, which enhances resistance to failure and defects, but too low wettability can also cause premature failure of the joints. Additionally, this study identifies key process behaviours, including the tendency for increased instability at higher wire feed rates and the significant role of bead morphology in determining mechanical performance. By elucidating these process–property relationships, this research provides a valuable framework for selecting appropriate MIG brazing parameters tailored to specific applications. The findings significantly contribute to the development of process control strategies aimed at enhancing joint reliability, offering critical insights for industries focused on optimizing brazing techniques to achieve improved structural integrity and overall performance in their applications.