Environmental protection, resource conservation and CO2 reduction require new joining concepts for effective multi-material design in automotive lightweight construction. The thermal joining of dissimilar materials, especially the combination of aluminum alloys and steel, is associated with difficulties. Different material properties, such as melting point and coefficient of thermal expansion, complicate joining processes. Furthermore, the insolubility between these materials results in the formation of intermetallic phases. These brittle phases reduce the load-bearing capacity and quality of the joints. For this reason, a new joining technology for overlap configurations of dissimilar materials was developed. A laser beam melts the lower joining partner through a cavity of the upper joining partner. The created melt pool moves upwards into the cavity of the upper joining partner due to contactless induced Lorentz forces of an AC-magnetic system. The displaced melt creates a form-fit and material-fit joint after solidification. The advantage of this joining technology is the absence of filler materials and expensive auxiliary joining elements. In this study, this new approach was tested for spot- and line shaped joints between 1 mm steel (DC 01) and 2 mm aluminum alloy (EN AW 5754). The process stability and reproducibility were analyzed by high-speed camera recordings. The filling of the cavity was investigated using cross sections. Energy-dispersive X-ray spectroscopy (EDX) and microhardness measurements according to Vickers were carried out for the characterization of the joint and the qualitative identification of intermetallic phases. The mechanical properties of the joints were analyzed by tensile shear tests. The results show that the new approach works in principle. The intermetallic phases are mostly the same known from the state of the art of laser welding processes between steel and aluminum alloys. The values of tensile shear tests are comparable to studies of laser beam welded and resistance spot welded steel and aluminum lap joints.