His draft rights were then traded to the Milwaukee Bucks, along with the draft rights of the 54th pick, Sandro Mamukelashvili, and two second round draft picks, for Isaiah Todd.
Kalaitzakis' contract with Panathinaikos had a buyout amount of $300,000, which was paid by the Bucks.
On August 11, 2021, the Milwaukee Bucks announced that they had signed Kalaitzakis.
Kalaitzakis made his debut in the NBA on October 19, 2021, coming-off from bench with two rebounds in a 127–104 win over the Brooklyn Nets.
On December 3, he was waived by the Bucks after nine appearances.
On December 30, 2021, Kalaitzakis was claimed off waivers by the Oklahoma City Blue of the NBA G League
where he played in 31 regular season games and averaged 10.1 points, 3.9 rebounds and 2.1 assists in 19.6 minutes per game.
On April 5, 2022, he signed with the Oklahoma City Thunder for the rest of the season.
Kalaitzakis played four games for the Thunder, averaging 41.5 minutes and 17.5 points per game.
On July 25, 2022, Kalaitzakis signed a two-year contract with Panathinaikos, returning to Greece and reuniting with his twin brother Panos.
In 26 EuroLeague games (16 starts), he averaged 2 points and 1.1 rebounds in 10 minutes per contest.
Additionally, in 29 domestic league matches, he averaged 6.4 points, 1.8 rebounds and 1.2 assists in 13 minutes per contest.
On September 4, 2023, Kalaitzakis was released from the Greek powerhouse.
On December 7, 2023, Kalaitzakis signed a one-year contract with Tigers Tübingen of the German Basketball Bundesliga.
Kalaitzakis was a member of the junior national teams of Greece.
1999
Georgios Kalaitzakis (Greek: Γιώργος Καλαϊτζάκης ; born January 2, 1999) is a Greek professional basketball player for Tigers Tübingen of German Basketball Bundesliga (BBL).
He is a 2.01 m (6'7") tall small forward. As a teenager, Kalaitzakis used to be regarded as one of the top young European prospects in his age range.
2003
Their younger sibling Alexandros (born 2003) also plays basketball professionally.
2015
With Greece's junior national teams, he played at the 2015 FIBA Europe Under-16 Championship, the 2016 FIBA Europe Under-18 Championship, and the 2017 FIBA Europe Under-18 Championship.
2016
After playing with the junior youth clubs of Aris, Kalaitzakis began his professional career in 2016, with the Greek club Panathinaikos.
With Panathinaikos, he won the Greek Cup title in 2016, 2017, and 2019, and also the Greek League championship, in 2017, 2018 and 2019.
2018
In March 2018, Kalaitzakis announced his intention to declare for the 2018 NBA draft.
He later withdrew from the draft before the draft's withdrawal deadline.
He also played at the 2018 FIBA Europe Under-20 Championship, and the 2019 FIBA Europe Under-20 Championship, which he led in scoring, with an average of 19.7 points per game.
Kalaitzakis' twin brother Panos is a professional basketball player and had been Georgios' teammate in both the Lithuanian club Nevėžis Kėdainiai as well as Panathinaikos.
2019
On August 28, 2019, Kalaitzakis signed with Nevėžis Kėdainiai of the Lithuanian Basketball League, on a loan deal from Panathinaikos.
In 23 games played in the Lithuanian league's 2019–20 season, he averaged 12.2 points, 4.3 rebounds, 2.3 assists and 1 steal in 28.7 minutes per game.
2020
In April 2020, Kalaitzakis declared for the 2020 NBA draft.
However, he withdrew before the draft took place.
On August 11, 2020, Kalaitzakis re-signed with Panathinaikos through the end of the 2021–2022 season.
With Panathinaikos, he went on to win both the 2020–21 Greek Cup title and the 2020–21 Greek Basket League championship.
Kalaitzakis was selected by the NBA's Indiana Pacers, with the 60th overall pick of the 2021 NBA draft.
