Tasis Papaioannou was born in Athens on March 1953. He studied Architecture in National University of Athens, from which he graduated on 1976. He returned at the University on 1982 as scientific collaborator and he systematically occupied with the teaching of Architectural Synthesis. Today, he is a professor on sector 1, sector of Architectural Synthesis, of the Department of architecture of NTUA.

He cooperates with Dimitris Isaias, with whom he has established an architectural studio since 1979. In cooperation with Isaias and many other architects, Papaioannou has developed many private and public buildings that possess a prominent place in every Greek and international bibliography. He has participated in many important national architectural competitions and has been awarded for his proposals numerous times. His participations constitute a great amount of his architectural work, but also a field of research.

On 2000 his project "Office Building in Athens" won the first prize of Hellenic Institute of Architecture in the category of "Work and common use". On May o 2003 he presented with the artist Alekos Fasianos the exhibition "Painted and Architectural Apace" in "Athinaes". On 2005 the same exhibition was hosted in the Gallery of Thessaloniki Casa Bianca. On 2009 Theoharaki Institution presented the common exhibition of Papaioannou and Fasianos with the title: "Color and Light in Painting and Architecture".

He has published many articles for architecture in Greek and international books, magazines and journals. He has presented his work in many architectural exhibitions in Greece and abroad. He has written with Fasianos the book "City without beginning" (edition Kaktos, 2004) and he has written with other architects the book "Architecture. Ideas that come together, ideas that become lost" (edition Papasotiriou, 2004). On 2005 he wrote "Everyday Architecture" (edition Kastanioti) and on 2008 the book "The Architecture and the City" (edition Kastanioti).