He painted genre works, portraits, local figures, architectural subjects, interiors with figures and animals. But he is best known for his orientalist paintings.
He was sent to Paris under the patronage of King Otto of Greece and studied under Jean-Léon Gérôme, French painter and professor at the Ecole des Beaux-Arts, and under Jean-Jules-Antoine Lecomte du Nouy, both known for their orientalist paintings.
Ralli then travelled widely in North Africa and the Middle East, settling for a while in Cairo, Egypt. Here he found his inspiration for the romantic mysticism and suggestive sensuality of his many orientalistic paintings. His other genre paintings were often nostalgic recollections of the life and customs of his Greek homeland, which he portrayed with a delicate and moving reverence.