<p>Magnesium, the lightest structural metal, holds immense promise for transforming the automotive industry through lightweight vehicle castings. This review examines magnesium’s suitability by discussing its intrinsic properties and processing techniques. By tracing the evolution of magnesium casting technologies—from conventional methods to advanced processes such as high-pressure die casting and Thixomolding; it highlights state-of-the-art methodologies for manufacturing lightweight vehicle components. The paper critically evaluates key challenges in magnesium casting, including corrosion resistance, alloy development, cost considerations, and recyclability, while exploring innovative solutions to address these issues. Through an analysis of existing research and industrial applications, the review demonstrates magnesium’s potential to enhance fuel efficiency, reduce emissions, and improve overall vehicle performance. It emphasizes the need for continued research and interdisciplinary collaboration to fully realize magnesium’s potential in lightweight vehicle castings, thereby supporting a sustainable and environmentally responsible automotive future. Furthermore, based on a comparative assessment, the review identifies thixomolded magnesium as a strategically advantageous alternative to aluminium gigacasting for electric vehicle applications. This is attributed to its lower density, greater design flexibility, reduced processing constraints, and potential for improved life-cycle sustainability. Overall, the review positions magnesium particularly thixomolded magnesium as a key enabling material for next-generation lightweight and sustainable mobility solutions.</p>