He is Vice Rector of the Technological Education Institute of Thessaly in Greece (formerly TEI of Larissa), responsible for the IT and Infrastructure Systems of the Institution.

From 2005 to 2013 he was Head of the Department of Tourism Business Administration at the Technological Education Institute of Larissa and since 2000 he is a Lecturer in the Postgraduate Program of Tourism Business Administration at the Hellenic Open University.

In the past, Dr. Velissariou was employed by the Greek Tourism Organization and as a Senior Consultant in the Consulting Company IN.DE.CO. S.A. and he has participated in several European Business Projects, in the framework of Interreg, Phare CBC, NOW (New Opportunities for Women), TERRA Program, EQUAL, E.U.-Town Twining Program, Leonardo Da Vinci, Phare Lien Program and others.
Professor Velissariou is author of 3 books, has contributed in many collective editions and published several papers in international scientific journals in the field of tourism. He has presented papers at International Scientific Conferences and has conducted extensive research in the field of Tourism and Economics.
In addition, he is a member of the editorial board of the MTOL (Transactions International journal ISSN: 1790-9899), the PRIME (Practical Research Issues in Management & Economics ISSN: 1791-5767), the Revista de turism - studii si cercetari in turism (ISSN 18442994), a member of the Editorial Advisory Board of the Ecoforum Journal (ISSN: 2344 – 2174) and also a member in many Scientific Conference Committees in the field of tourism worldwide.