González was born in Barcelona, where his father and grandfather were skilled jewellers and metalworkers. During his apprenticeship in his father's workshop, he learned the techniques of cutting, soldering and forging metals. In 1900 the González family moved to Paris, where Julio renewed his acquaintance with Picasso, an old friend from Barcelona. He continued making decorative metalwork and only in the late-1920s did he begin to make sculptures, influenced by the cubist work of Picasso. González had learned the technique of oxyacetylene welding at a car factory near Paris, and even helped Picasso to make a number of large, forged, iron sculptures.