After withdrawing from the study of law, Mantourides staged traditional Greek theatre at the outbreak of World War II. His war service was undertaken in an entertainment unit. He gained further successful experience in producing theatre after the war but, with a deteriorating political environment, he emigrated to Australia. He found employment in the Sydney Telephone Exchange. He remained devoted to the theatre and established the Hellenic Theatrical Group in 1950. For his contribution to Greek community life, he as awarded an Honorary Diploma by the Greek Orthodox Community of Sydney and New South Wales in 1979. After a very successful career as a producer of Greek drama in Australia for thirty years, he contracted muscular dystrophy and died not long after.