[34] In December 2012, a few days after turning 18, Antetokounmpo signed a four-year deal with Spanish club CAI Zaragoza,[35] reportedly including NBA buyouts after each season.

[45] On December 12, he recorded a near triple-double with 11 points, 12 rebounds, and 8 assists, helping the Bucks snap the Golden State Warriors' 24-game unbeaten start to the season with a 108–95 win.

[50] A couple of weeks later, Antetokounmpo recorded 27 points and 13 rebounds and made his first game-winning buzzer-beater, a 15-foot turnaround jumper which gave the Bucks a 105–104 victory over the New York Knicks.

Antetokounmpo led the Bucks in every one of the five major statistical categories (points, rebounds, assists, steals, and blocks) in the 2016–17 regular season, becoming only the fifth NBA player to do so after Dave Cowens, Scottie Pippen, Kevin Garnett, and LeBron James; Nikola Jokić has since matched it.

[63] He averaged almost 27 points during the season, earning his second straight All-Star nomination and All-NBA selection,[64] and broke Kareem Abdul Jabbar's franchise record for triple-doubles.

He helped the Bucks advance to the second round of the playoffs for the first time since 2001 after scoring 41 points in a 127–104 win in Game 4 over the Detroit Pistons for a four-game sweep.

[83] On December 19, Antetokounmpo made a career-high five three-pointers to lead Milwaukee over the Western top seed, the Los Angeles Lakers and helped the Bucks claim the NBA's best record at 25–4.

[84][85] During the season postponement that lasted from early March to the end of July, due to the COVID-19 pandemic, Antetokounmpo claimed to not have a basketball hoop to practice with.

In a stark reversal of their upset loss the prior year, Antetokounmpo led the Bucks to a four-game sweep, closing out the series with his first playoff triple-double in Game 4.

[95] Antetokounmpo also led the Bucks to a seven-game series win over the Brooklyn Nets in the Eastern Conference Semifinals, where he averaged 31.9 points, 12.9 rebounds, and 3.6 assists per game.

On June 29, 2021, Antetokounmpo suffered an injury to his left knee during the third quarter of Game 4 of the Eastern Conference Finals against the Atlanta Hawks after slamming into Clint Capela and landing awkwardly, resulting in a gruesome hyperextension.

[99][100] The series returned to Milwaukee at a 2–2 deadlock, yet the Bucks ended up winning both Games 5 and 6 in his absence, advancing to the NBA Finals for the first time in 47 years.

[107][108] He posted series averages of 35.2 points, 13.2 rebounds, 5.0 assists, 1.2 steals, and 1.8 blocks, and was subsequently named NBA Finals MVP by a unanimous vote.

[111] On October 19, 2021, after receiving his first NBA championship ring in the annual pre-game ceremony, Antetokounmpo recorded 32 points, 14 rebounds, and seven assists in a 127–104 season-opening win over the Nets.

[122] On March 29, Antetokounmpo scored 40 points, grabbed 14 rebounds, delivered six assists, and had a game-deciding block on Joel Embiid in the final seconds to lead the Bucks to a 118–116 victory over the Philadelphia 76ers.

[127] On May 1, in Game 1 of the Eastern Conference Semifinals, Antetokounmpo recorded his second career playoff triple-double with 24 points, 13 rebounds, and 12 assists in a 101–89 win over the Boston Celtics.

It tied him with Hall of Famer and former two-time NBA Defensive Player of the Year Award winner Sidney Moncrief for most selections in franchise history.

[139][140] On November 4, Antetokounmpo recorded his 30th career triple-double with 26 points, 14 rebounds and 11 assists in a 115–102 win over the Minnesota Timberwolves to improve to 8–0, the best start to a season in Milwaukee Bucks franchise history.

[147] On February 2, Antetokounmpo scored 20 of his 54 points in the fourth quarter, along with 19 rebounds and the Milwaukee Bucks overcame a 21-point deficit to beat the Los Angeles Clippers 106–105 for their sixth consecutive victory.

[171] On March 26, Antetokounmpo posted his 44th career triple-double with 29 points, a season-high 21 rebounds, 11 assists and 3 blocks in a 128–124 double overtime loss against the Los Angeles Lakers.

[193] Greece finished 11th in the tournament after they failed to advance past the second round, which was regarded as a disappointing result in national and international sports media.

On August 25, 2022, Antetokounmpo scored a national team career-high 40 points, along with 8 rebounds and 5 assists, in a 94–100 overtime loss to Serbia in the 2023 World Cup qualifiers.

Highly athletic and versatile, Antetokounmpo is often recognized as one of the best all-around players in the NBA, and many analysts have declared him "positionless" and as embodying the future of the league.

[208][209] His rare combination of size and speed frequently enables him to cross half a court in a single dribble and blowing past multiple defenders.

Most famously, the Toronto Raptors built a 'wall' of lengthy, adept defenders to neutralise Antetokounmpo's paint dominance in their 2019 Conference Finals victory.

[203] Antetokounmpo is also recognized as an elite defensive player, capable of guarding all five positions but more often deployed in a "free safety" role that allows him to roam the paint and discourage attacks on the rim.

[224] In September 2022, Antetokounmpo joined as an executive producer for National Geographic's documentary The Flagmakers, which focuses on the large population of immigrant employees working at an American flag factory.

On March 13, 2020, Antetokounmpo and his family pledged to give $100,000 to the staff of the Fiserv Forum who were unable to work during the suspension of the 2019–20 NBA season because of the COVID-19 pandemic.

[248] In March 2023, Giannis, along with his brothers, Alex, Thanasis, and Kostas, became minority owners in the Major League Soccer club Nashville SC.

[249] In June 2023, Giannis and his brothers Thanasis, Kostas and Alex expanded their investment portfolio, overseen by Ante Inc., by becoming shareholders and owners of the Canadian online confectionary retailer, Candy Funhouse.