He was awarded with International Peace Party 2nd prize in Istanbul, in 1965, for the work, War Game, which he staged and produced.

In 1966, Onay shared the "Grand Prix of the Festival Mondial du Theatre de Nancy" with a Brazilian theater troop, for the piece Long Creek, which was adapted from Yaşar Kemal’s novel, Yer Demir, Gök Bakır (Iron Earth, Copper Sky) by Nihat Asyalı.

In 1973, he was invited by the ITI, (German Centre of the International Theatre Institute,) as a guest student to participate on the urban stages of the city of Essen and Berlin.

In 1974, he helped start a new theatre called The Contemporary Stage, in Ankara, where he, from 1975 to 1978, produced and directed plays, adapted from Nazım Hikmet’s Yusuf and Menofis, Nihat Asyalı's Strike, and Gladkov's The Cement.

Later in 1984, he directed a play, adapted from a novel by Hans Fallada, called Little Man, What Now?, and a self-written cabaret These Price Raises Are Up Against Me.

From 1985 to 1989 he produced and directed his own pieces abroad, Those Who Were Left in Araf and Mystery of Karagöz in Amsterdam, The Death of An Artist in Paris, a play about peace for children, Our Songs Must Not Die, in the Hebbel Theater, Berlin.