Fountoukidis was born in 1942 in
Panteleimon, Kilkis. He started playing football at his hometown club
Aris Panteleimon and in 1960 he moved to
Apollon Kalamaria. In 1963, he was transferred to
MENT and from there he was acquired by
PAOK in the summer of 1966, a move that was made possible thanks to the collaboration of PAOK administrative leader
Giorgos Pantelakis with the team's coach
Nikos Pangalos. Although he started his career as a center forward, at PAOK he established himself as a central defender and quickly became irreplaceable. Fountoukidis worked in construction when he was young and thanks to his impressive physical qualities, he was nicknamed
"The Wall" (). He is
PAOK 5th all-time appearance maker with 395 games in total (336 in the league) and won with the
White-blacks of the North the
1972 and
1974 editions of the Cup and the
1976 league title. Fountoukidis was assistant of
Gyula Lóránt when the Hungarian manager returned to PAOK for a second spell in 1980 and took over as caretaker coach after Lóránt's passing. Aristos coached PAOK in the
1981 Greek Cup final against
Olympiacos. ==Death==