As a conductor, Antoniou worked with orchestras, small and large ensembles, and musical organizations all over the globe.
In 1974 he was engaged as assistant director of contemporary activities at the Tanglewood Music Center in Lenox, Massachusetts, and held that position until the summer of 1985.
[9] In 1995 he was the Member of International Honorary Committee of the Worldwide Dictionary of Music[10] (Editor: Olympia Tolika) of European Art Center of Greece.
Over two hundred of his works have been published by Bärenreiter Verlag (Germany), G. Schirmer (USA) and Philippos Nakas (Greece).
In the 1970s, the influences of Jani Christou, Bernd Alois Zimmermann, and Krzysztof Penderecki became evident in his works.