Th. Papayiannis was born in Elliniko, Ioannina, in 1942. 
From 1961 to 1966 he studied at the Athens School of Fine Arts on a scholarship, next to Yiannis Pappas.

In 1967 he studied ancient Greek Art and the Art of the Mediterranean Basin, on a two-year domestic Scholarship from the Government Scholarship Service (I.K.Y). His Mediterranean journeys took him to Egypt, Asia Minor, Cyprus, South Italy and Sicily.

Th. Papayiannis has been a Professor of Sculpture at the Athens School of Fine Arts.

He lives and works in Athens, Greece.