[1][2] Karoulias started his football career at the academies of AEK Athens, where in 1973 he was promoted to the men's team under Stan Anderson.
[3] The big leap in his career took place in the summer of 1980, when he transferred to Panathinaikos.
He was distinguished for his spirited game, while the highlight of his career was his participation as a starter in the team that reached the semi-finals of the European Cup in 1985.
Karoulias played for the first time with Greece on 14 October 1981, in the home match against Denmark (2-3), for the qualifiers of the 1982 FIFA World Cup.
[4] After he retired as a footballer, Karoulias followed a career as a coach, with his most important moment being his brief presence at the bench of Panathinaikos in 1997,[5] while he has also worked in other clubs, including Athinaikos, Panargiakos, Olympiakos Nicosia,[3] Anorthosis Famagusta,[6] Proodeftiki, Kallithea and Apollon Smyrnis from 1996 until 2011.