John Christoforou was born to Greek parents in London. Both died when he was still a child, so he spent his childhood years between Athens and London and was raised by various relatives. He studied at the School of Fine Art, Athens.

During the Second World War, he served five years as a navigator for the British Royal Air Force.

At the end of the war, although he was encouraged to remain with the RAF, he held hard to his vision of a career in art. His first show was in London, at the twenty Brook Street Gallery and was followed by others at Gallery One and Gimpel Fils, as well as group shows at the Institute of Contemporary Art and the Whitechapel Gallery.

In 1956, he married Ruth Fox, and a year later the couple moved to Paris, a city they felt would offer more opportunity to develop and exhibit his work. 

In 1960, he had the first of several shows at the Rive Gauche gallery, and in 1965 he won the International Association of art Critics prize in London. While showing widely in France, he began to attract increasing attention across Europe exhibiting in the Netherlands in 1970 and having a retrospective in the Randers Kunstmuseum in Denmark in 1974.

He was particularly popular in the Nordic countries and continued to show in Scandinavia for the next thirty-five years.

Christoforou became known for his powerful expressionist figure paintings, reflecting solidarity and a slight dystopian view of the human condition. His work was of heroic scale, with vivid colour, dynamic blacks and vigorous brushwork.

His work can be found at the National Gallery of Greece, the Goulandris Museum of Contemporary Art, the Museum des 20 Jahrhunderts, Vienna, the Nouveau Musee Olympique, Lausanne, the Artotheque, Montpellier, the Artotheque, Angers, the Bibliotheque Nationale-Cabinet des Estampes, Paris, the Contemporary Art Society, London and in many private collections in Athens and internationally.