Onassis was born in Karatass, a suburb of Smyrna (now İzmir, Turkey) to Socrates and Penelope Onassis (née Dologu), who married Socrates at the age of 17. Onassis had one full-sister, Artemis, and two half-sisters, Kalliroi and Merope, by his father's second marriage following Penelope's death at the age of 33. Socrates Onassis came from the village of Moutalasski (now named Talas), near Cappadocia in Asia Minor, which is the present-day Kayseri province, in central Turkey. In 1923, Aristotle Onassis left for Buenos Aires, Argentina, by Nansen passport and got his first job with the British United River Plate Telephone Company.
He was one of the world's richest men, but it was the glamour of the women in his life, such as Maria Callas and Jackie Kennedy, which brought him real fame.
Onassis's childhood was dominated by the principles of the Orthodox Church. Unsurprisingly, this upbringing influenced him throughout his life.
While not an openly religious man, Onassis retained many of the qualities imparted to him through the church.
He left Smyrna in 1922, travelling to Argentina, where he revived the family tobacco business by building a new market for the product there. In a few years the business flourished and Onassis had made his first million.
The tobacco business was too limited for a man of Onassis' dreams and, in the early 1930s, he purchased his first ships.
It took him only a few days to expand his fleet and, by the end of the decade, he had entered the tanker business, which was potentially far more profitable.
In 1946, Onassis married Tina Livanos, the daughter of Stavros Livanos, an important Greek shipowner. Tina had American citizenship and they set up home in New York.
Later, Onassis became brother-in-law to Stavros Niarchos, another shipowner and with that, the three men, Onassis, Livanos and Niarchos, formed the most powerful shipping group in the world. Rivalry would later develop, but it remained a powerful force.
In 1957, Onassis turned his attention skywards and took over the failing Greek National Airline, making it into a private business, Olympic Airways of Greece.
Onassis divorced his wife in 1961. He had a long relationship with the singer, Maria Callas, but in 1968 married the most famous woman in the world at that time, Jacqueline Bouvier Kennedy, the widow of President John F. Kennedy.
Tragedy struck in 1973, when Alexander Onassis, Onassis's son from his first marriage, died in a plane accident. Onassis was devastated. Not long after, on 15 March 1975, Onassis died. He was buried on his island near his son Alexander.