This chapter covers his business during the first period of his entrepreneurial activity, from 1924 to 1946, when he set up his trading and tramp shipping company. During these first 22 years, he was unknown to the public. The aim is to investigate Onassis’s activities in America as well as in Europe and to reveal the significance of the beginnings of his business. During this period Onassis advanced his career within the Greek maritime tradition established by the Vaglianos, but also led the way to break this tradition, re-invent it, and advance it further. He created the foundations of his Empire, with Buenos Aires as the basis of his entrepreneurial activities. In the 1920s based on his family business know-how and network he collaborated with his father and uncle in Greece, and with his first cousins in Argentina, to found a sound business of tobacco imports. In the 1930s, Onassis devoted himself into learning about Greek and Norwegian shipping methods and techniques and was able to expand and re-invent them. By 1940, he had made the choices that marked his path to global shipping: specialization in tanker shipping, offshore companies and flags of convenience