Papantoniou began his professional career in the 2007–08 season with the Greek League club Maroussi.

[4] On September 30, 2018, due to the injuries of Phil Goss and Apollon Tsochlas, Papantoniou joined PAOK on a monthly contract.

Papantoniou then finished the season with Panionios, leading them to avoid relegation, with an average of 11.3 points and 3.9 assists per game.

He signed back with Larisa on November 10, 2021, after starting the season in Romania with Craiova.

As a member of the junior national basketball teams of Greece, Papantoniou played at the 2006 FIBA Europe Under-16 Championship.