A process of making a multilayer metallic casting includes steps of simultaneously forming a first layer of a first metallic material and a second layer of a second metallic material using a high speed continuous casting process, and continuously bonding the first and second layers to form a integrally cast multilayer metallic casting. The process may be performed using a twin-roll type continuous casting system having a continuous casting mold that includes a first mold compartment for receiving a molten first metallic material and a second mold compartment for receiving a molten second metallic. The molten first and second types of metallic material are quickly solidified into semi-solid shells and are pressed together by opposed casting rolls, creating a metallurgical bond between the first and second types of metallic material in order to form an integrally cast multilayer metallic casting. The process permits the high speed efficient manufacturing of near net shape multilayer metallic castings.