Costas Alexiou was born on the island of Skyros.
In 1941 he enrolled at The School of Fine Arts, Athens, where he studied painting under Constantinos Parthenis and Umberto Argyros.
Alexiou’s work has a poetic feeling that is expressed through a selective color palette, simplicity and realism.
He worked at the artistic department of Kerameikos and The National Archaeological Museum of Greece. For this reason a number of his works depict archaeological sites in Athens.
His work can be found in the collections of: The Municipality of Athens, The Municipality of Piraeus, The National Bank of Greece and in many public and private collections in Greece, and internationally.