Alekos Fassianos was born in Athens in 1935. He studied painting at the Athens School of Fine Arts (1956 – 1960) under Yiannis Moralis. He continued his studies in lithography at the École des Beaux-arts (1960 – 1963) as a fellow of the French government.

From 1960 onwards, he has presented his work in Athens in solo exhibitions at Gallery A23 (1962) and at Zygos art gallery (1963). He held regular exhibitions at the Zoumboulakis Galleries (1971, 1975, 1977, 1979, 1980, 1982, 1983, 1986, 1989, 1990, 1991, 1992), and at the same time he exhibited in Paris, Munich, Hamburg, Tokyo, Milan, Malmö, etc. He also took part in group exhibitions and international events, including the Salon Comparaisons in Paris in 1970, the Europalia 1982 in Brussels, the Sao Paulo Biennale in 1971, the Venice Biennale in 1972, the Baden-Baden Biennale in 1985, etc.

He also worked as a stage designer and a book illustrator; he published articles and books, he designed posters, medals and jewellery. He lived in Athens and Paris and he was honoured by both Greece and France. In Greece he was presented with the Prize of Arts and Letters by the Athens Academy in 1999 and he also became Knight of the Order of Arts and Letters of France. He is a member of the Chamber of Fine Arts of Greece.