Selionis started his career from Kissavos Sykourion before he joined the youth section of AEL in 1974 under Argentinian coach Horacio Moráles.
[4] After his retirement he coached various local clubs such as Haravgi and Ikaros Neapolis and later he became the longest serving arch-coach and also secretary of the Larissa FCA.
He led the Larissa FCA squad to the 2010 PanHellenic final losing out to the 2011 UEFA Regions' Cup representation of Greece after a 4-1 defeat at the Leoforos Alexandras Stadium .
[5][6]Selionis was responsible for various OFI's signings of young talents from the Larissa area throughout the years (Ilias Kotsios, Konstantinos Mangos, Pavlos Adamos, Vasilios Koutsianikoulis).
[7] Selionis, known for his pleasant personality, passed away in Larissa due to illness caused by cancer, at the age of 65.