Smart materials that can sense and respond to environmental stimuli such as temperature, stress, magnetic fields, and electric currents are transforming the design and functionality of engineering systems across diverse sectors. From aerospace actuators to biomedical implants, these materials offer tailored performance and adaptability, often mimicking biological responsiveness. Concurrently, metal additive manufacturing, or metal 3D printing, is redefining possibilities in fabrication, offering geometric complexity, customization, and material efficiency that traditional methods cannot match. The intersection of metal Additive Manufacturing and smart materials presents a powerful opportunity: manufacturing functional, responsive structures with tailored properties, spatially varying functionalities, and integrated sensors or actuators from the ground up. This chapter proposes to explore the current landscape, challenges, and prospects of fabricating smart materials using Additive Manufacturing.