Actor, writer, director, composer and musician, Stefo Nantsou has worked with a number of Australian theatre companies, including Freewheels Theatre, Sidetrack Theatre and The Torch Project, and has also specialised in producing theatre for young people. In 1987 a collaboration between Nantsou, Silvio Ofria, Adam Hatzimanolis and Sidetrack Theatre, resulted in Kin (q.v.), a musical play which explores cultural differences, and more particularly identity among the displaced.
In 1988 Nantsou founded Zeal Theatre (q.v.) in Newcastle, and over the next eight years established a strong presence in the Hunter Valley region, touring school productions and presenting public seasons in and around Newcastle. Zeal Theatre has toured productions throughout much of Australia and produced shows at some of the country's major children's festivals. It has also staged productions in more than twenty countries, while also running workshops with students and youth arts companies. In 1996 Nantsou relocated Zeal Theatre to Melbourne. The company's first production after moving to the Victorian capital was The Stones. Based on a true event in which two boys killed a motorist after throwing rocks from a freeway overpass, it has since become Zeal's most successful show. Up to 2006 it had been performed over 900 times in Australia, Europe, Asia and North America. The play has also been translated into Dutch, Welsh, Hungarian, Danish and German.
Although only one of his plays has been officially published, by 2006 Nantsou had written or co-written over 35 works and directed more than 65. As an actor he has also performed in well over 80 productions. To date Nantsou's Zeal Theatre had received five Newcastle CONDA Awards (1989-2005), a New South Wales Frater Award (1997), a Best New Work Award for TheatreHaus (2002), a 2002 Dutch Theater Award, the Critics Choice Prize in Budapest (2003) and the International ASSITEJ Honorary President's Award for outstanding services to theatre for young people in Montreal (2005).