[5] He made his pro debut in the 1st-tier level Greek League, during the 2012–13 season, on 26 November 2012, in a home game against Panelefsiniakos.

[6] Charalampopoulos made his debut in the European-wide top-tier level EuroLeague, during the 2013–14 season, in a road game against Lokomotiv Kuban, on 13 December 2013.

His loan was prematurely recalled on January 8, 2020, and Charalampopoulos rejoined Olympiacos for their EuroLeague campaign, after a rather successful stint with Ionikos.

In 13 EuroLeague games total with Olympiacos (11 during the 2020–2021 season), Charalampopoulos averaged a playing time of only 7.5 minutes, as well as 2.5 points and 0.6 rebounds per contest.

On August 1, 2021, Charalampopoulos signed a multi-year deal with Umana Reyer Venezia of the Italian Lega Basket Serie A (LBA).

[13] On July 17, 2022, Charalampopoulos signed with Victoria Libertas Pesaro of the Italian Lega Basket Serie A (LBA).

In the summer of 2014, Charalampopoulos played at the FIBA Europe Under-18 Championship and helped Greece reach the fourth place of the tournament.

[18][19] In the summer of 2015, Charalampopoulos suffered a right ankle injury in a friendly game against the USA, and doctors initially said that it would be difficult for him to play at the 2015 FIBA Under-19 World cup.

In a game against France, he had 13 points, 10 rebounds, and 11 assists, making him the first player since Lithuania's Martynas Andriuškevičius to record a triple double at the same tournament.