This chapter explores the ultrasonic additive manufacturing (UAM) advanced solid-state metal additive/subtractive manufacturing process that combines ultrasonic welding and computer numerical control milling to fabricate solid metal components, layer-by-layer, from metal foils. The chapter will discuss the three key abilities of UAM: complicated geometries, dissimilar material bonding, and object embedment. The combination of these three key abilities places UAM as a most attractive method with which to create metal matrix-based freeform smart structures for high-value engineering applications. © 2015 Elsevier Ltd. All rights reserved.