A novel resistance element welding was employed for dissimilar joining of electro-galvanized DP780 steel to 6061-T6 aluminum alloy. Compared with traditional resistance spot welding, the change of load bearing part resulted in higher joint strength and energy absorption capacity. Microstructures of dissimilar joints vary according to the distance from the weld center. Intermetallic compound layers were formed at the Al/rivet interface and Al/steel interface in the resistance element welding joints and resistance spot welding joints, respectively. The fatigue strength, and fatigue fractographs of the dissimilar joints were obtained and discussed. Resistance element welding joints showed higher fatigue strength than resistance spot welding joints, with the fatigue limit of 1800 and 900 N, respectively. The fatigue fracture modes of both types of joints were dependent on the load levels. At high load levels, the REW joints and RSW joints underwent pull-out and interfacial fracture, respectively. At low load levels, both joints underwent through-thickness fracture.