Atlanta Hawks (2007–2016) All-Rookie honors (2007–2008) On June 28, 2007, Horford was selected by the
Atlanta Hawks with the third overall pick in the
2007 NBA draft. On July 9, he signed his rookie scale contract with the Hawks. As a rookie in
2007–08, Horford was the only player unanimously selected to the
NBA All-Rookie First Team; he was also runner-up for Rookie of the Year honors and was named Rookie of the Month on four occasions. Horford became the first Atlanta draftee to earn first team honors since
Stacey Augmon in 1991–92. Horford averaged 10.1 points, 9.7 rebounds, 1.5 assists, 0.9 blocks, 0.7 steals and 31.4 minutes in 81 games (77 starts). The Hawks finished the regular season with a 37–45 record and entered the playoffs as the eighth seed in the Eastern Conference. In their first round match-up with the
Boston Celtics, Horford helped the Hawks take the eventual champions to seven games, losing the series 4–3. In the series, Horford averaged 12.6 points and 10.4 rebounds per game.
Back-to-back All-Star selections (2008–2011) In
2008–09, Horford started all 67 games he played, averaging 11.5 points, 9.3 rebounds, 2.4 assists, 1.4 blocks and 0.8 steals in 33.5 minutes. With a 47–35 record, the Hawks entered the playoffs as the fourth seed in the East. Horford helped the Hawks advance to the second round where they were swept by the
Cleveland Cavaliers; Horford missed Game 2 of the series due to injury. Horford had an outstanding season in
2009–10, becoming the first Hawks draft pick to earn an All-Star berth since
Kevin Willis did so in 1992. Horford contributed 14.2 points, 9.9 rebounds, 2.3 assists, 1.1 blocks and 0.7 steals in 35.1 minutes (.551 FG%, .789 FT%), appearing in 81 games. He ranked eighth in the NBA in field goal percentage, 10th in rebounds, tied for ninth in offensive rebounds (2.9), and 26th in blocks. Horford had a team-leading 39 double-doubles, which was tied for 11th in the NBA. On November 1, 2010, Horford signed a five-year, $60 million contract extension with the Hawks. During the
2011 NBA All-Star Weekend, Horford was an All-Star for the second straight year, In 77 games in
2010–11, Horford posted averages of 15.3 points, 9.3 rebounds, 3.5 assists, 1.0 blocks and 0.8 steals (.557 FG%, .500 3FG%, .798 FT%). He ranked fifth in the NBA in field goal percentage, 28th in blocks and 16th in efficiency (22.5). Horford was also one of the top all-around rebounders in the league, finishing 11th in rebounds, seventh in defensive rebounds (7.0) and tied for 24th in offensive rebounds (2.4). He had 36 double-doubles (tied for ninth in NBA), including one 20/20 game. He was named
Third-Team All-NBA. With a 40–26 record, the Hawks entered the playoffs as the fifth seed in the East. Horford missed an additional three playoff games before returning to action in Game 4 of the Hawks' first round series against the
Boston Celtics. He played out the series, which the Hawks lost in six games.
Career-best season (2012–2013) In the
2012–13 season, Horford started all 74 games he played, averaging a career-high 17.4 points, career-high 10.2 rebounds, 3.2 assists, 1.1 blocks and career-high 1.1 steals in 37.2 minutes. He recorded 43 double-doubles (20 20-point/10-rebound games), including one in points and assists. Horford scored 20-plus points in nine consecutive games (February 11 – March 3) for the first time in his career. On November 26, 2012, Horford was named Eastern Conference Player of the Week for the first time in his career. On February 27, 2013, Horford scored a career-high 34 points in a 102–91 victory over the
Utah Jazz. With a 44–38 record, the Hawks entered the playoffs as the sixth seed in the East. In their first round match-up against the
Indiana Pacers, the Hawks were defeated 4–2 despite a playoff career-high 16.7 points per game from Horford over the six games.
Second injury-shortened season (2013–2014) Over the first 29 games of the
2013–14 season, Horford posted nine double-doubles and scored in double-figures 28 times, including 13 20-point outings and one 30-point game. Over this stretch, he averaged a career-best 18.6 points per game. However, another shoulder injury suffered on December 26, 2013, sidelined Horford for the rest of the season. Initially considered a "bruised right shoulder", the injury turned out to be a complete tear of his right pectoral muscle, and required season-ending surgery. Horford did not play in the postseason, where the Hawks lost in the first round to the
Indiana Pacers.
Return to All-Star form (2014–2016) In
2014–15, Horford played in 76 regular season games, the most since the 2010–11 season. On December 22, 2014, he was named Eastern Conference Player of the Week for games played from Monday, December 15 to Sunday, December 21. Horford earned the award for just the second time in his career. On January 13, 2015, Horford recorded his first career triple-double with 21 points, 10 rebounds and 10 assists in a 105–87 victory over the
Philadelphia 76ers. Six days later, Horford was named Eastern Conference Player of the Week for games played from Monday, January 12 to Sunday, January 18. On January 29, he earned his third All-Star nod as a reserve for the Eastern Conference in the
2015 NBA All-Star Game. In a brilliant stretch of play from December 7 to January 31, Horford scored in double digits in 28 consecutive games. Between December and January, the Hawks went 28–2 and had a franchise-best 19 game winning streak. Behind Horford and fellow All-Star teammates
Paul Millsap,
Kyle Korver, and
Jeff Teague, the Hawks finished the regular season with the best record in the Eastern Conference at 60–22, and advanced through to the Eastern Conference Finals for the first time since the 1960s, when the franchise was located in
St. Louis. There, they were defeated by the
Cleveland Cavaliers in a four-game sweep. In the
2015–16 season, Horford played in all 82 regular season games for the first time in his career. On November 11, 2015, Horford scored 26 points and made a career-high four three-pointers in a 106–98 victory over the
New Orleans Pelicans. On December 4, Horford scored 16 points against the
Los Angeles Lakers to extend his streak of double-digit games to 22, setting a career high. Horford's streak came to an end at 23 after scoring nine points against the
Oklahoma City Thunder in the Hawks' 24th game of the season on December 10. On February 12, 2016, Horford was named to replace the injured
Chris Bosh on the 2016 Eastern Conference All-Star team, thus marking his fourth All-Star selection. On February 28, Horford recorded his 200th career double-double with 13 points and 16 rebounds in an 87–76 victory over the
Charlotte Hornets. With a 48–34 record, the Hawks entered the playoffs as the fourth seed in the East. They reached the second round where they were swept by the Cavaliers for the second straight year.
Boston Celtics (2016–2019) On July 8, 2016, Horford signed a four-year, $113 million contract with the
Boston Celtics and said that he was looking forward to working with Celtics head coach
Brad Stevens and the rest of the team to bring a championship trophy back to Boston. Horford made his Celtics debut in their season-opening 122–117 victory over the
Brooklyn Nets on October 26, 2016, recording 11 points, five rebounds, and six assists. Horford appeared in the team's first three games of the season, but then missed nine straight games with a concussion. He returned to action on November 19 and had 18 points, 11 rebounds, and five assists in a narrow 94–92 road victory over the
Detroit Pistons. On March 19, 2017, Horford scored a season-high 27 points in a 105–99 loss to the
Philadelphia 76ers. In Game 1 of the Celtics' second-round playoff series against the
Washington Wizards, Horford nearly had a triple-double with 21 points, 10 rebounds, and nine assists during a 123–111 victory. The Celtics went on to reach the Eastern Conference Finals, where they lost to the
Cleveland Cavaliers in five games. On November 12, 2017, Horford returned from a two-game absence with a concussion and scored 21 points on 8-of-9 shooting to help the Celtics hang on to narrowly beat the
Toronto Raptors 95–94 for their 12th straight victory. On December 2, he had 14 points, five rebounds, and a career-best 11 assists in a 116–111 victory over the
Phoenix Suns. Two days later, Horford recorded 20 points, nine rebounds, and eight assists in a 111–100 victory over the
Milwaukee Bucks. On February 4, 2018, he made a 15-foot fadeaway jumper at the buzzer to lift the Celtics to a narrow 97–96 victory over the
Portland Trail Blazers, finishing with 22 points, 10 rebounds, and five assists. Horford made his fifth All-Star team when he was nominated as a reserve for the
2018 NBA All-Star Game. In Game 1 of the Celtics' first-round playoff series against the Bucks, Horford had 24 points and 12 rebounds during a 113–107 overtime victory. In Game 7, he had 26 points, eight rebounds, and three assists during a 112–96 victory. The Celtics went on to reach the Eastern Conference Finals, where they lost in seven games to the Cavaliers. On October 19, 2018, Horford had 14 points, 10 rebounds, and nine assists in a 113–101 loss to the Raptors. In December, he missed seven games with a sore left knee. On December 29, Horford scored 18 points with a career high-tying five three-pointers to go along with five rebounds and three assists in a 112–103 road victory over the
Memphis Grizzlies. On February 21, 2019, he recorded 21 points, five assists, and a season-high 17 rebounds in a narrow 98–97 loss to the Bucks. On April 1, Horford recorded his second career triple-double with 19 points, 11 rebounds, and 10 assists in a 110–105 victory over the
Miami Heat.
Philadelphia 76ers (2019–2020) On July 10, 2019, Horford signed with the
Philadelphia 76ers. An unrestricted free agent, he signed a four-year, $97 million (with $12 million in bonuses) contract. On October 23, 2019, Horford made his 76ers debut, recording 16 points, two rebounds, and three assists in a 107–93 victory over his former team, the
Boston Celtics. On November 4, Horford scored a season-high 32 points, alongside five rebounds, four assists, and two steals in a 114–109 loss to the
Phoenix Suns. The 76ers faced the Celtics during their first-round playoff series, but they were eliminated in a four-game sweep, with Horford only averaging 7.0 points per game.
Oklahoma City Thunder (2020–2021) On December 8, 2020, Horford was traded, alongside a 2025 first-round pick and the draft rights to
Théo Maledon and
Vasilije Micić, to the
Oklahoma City Thunder in exchange for
Terrance Ferguson,
Danny Green and
Vincent Poirier. Horford's arrival came three months after his former college coach,
Billy Donovan, left the Thunder. Horford made his Thunder debut on December 26, 2020, recording three points, three assists, and a season-high 13 rebounds in a narrow 109–107 victory over the
Charlotte Hornets. On February 5, 2021, Horford scored a season-high 26 points, alongside seven rebounds, eight assists, two steals, and three blocks in a 106–103 loss to the
Minnesota Timberwolves. On March 27, the Thunder announced that Horford would sit out the rest of the season as the team prioritized developing its younger players.
Return to Boston (2021–2025) First NBA Finals (2021–2022) On June 18, 2021, Horford was traded, alongside
Moses Brown and a 2023 second-round pick, to the
Boston Celtics in exchange for
Kemba Walker, the 16th overall pick in the
2021 NBA draft, and a 2025 second-round pick. On March 3, 2022, Horford helped the Celtics to a 120–107 victory over the
Memphis Grizzlies with a season-high 21 points and 15 rebounds. On May 7, 2022, in Game 3 of the
Eastern Conference Semifinals, Horford scored 22 points to go along with 16 rebounds, five assists, two blocks, and no turnovers in a 103–101 loss against the reigning champion
Milwaukee Bucks. Two days later in Game 4, he recorded a playoff career-high 30 points, along with eight rebounds on 11-of-14 shooting from the field and had a playoff career-high 5-of-7 shooting from three-point range in a 116–108 victory to tie the series at 2–2. On May 29, 2022, Horford had five points and 14 rebounds as he reached the
NBA Finals for the first time in his 15-year career when the Celtics defeated the
Miami Heat by a score of 100–96 in Game 7 of the
Eastern Conference Finals. Before doing so, Horford set a record for the most playoff games without an NBA Finals appearance, with 141. He also became the first Dominican to reach the NBA Finals. In Game 1 of the Finals four days later, Horford led the Celtics to a 120–108 comeback victory over the
Golden State Warriors with 26 points and six rebounds. He hit six three-pointers during the game, setting an NBA record for most threes made by a player in his Finals debut. The Celtics took a 2–1 series lead, but eventually lost in six games despite Horford's 19-point, 14-rebound outing during the 103–90 close-out loss in Game 6 on June 16.
Contract extension (2022–2023) On December 1, 2022, Horford signed a two-year, $20 million extension with the Celtics. On January 19, 2023, he had 20 points, 10 rebounds, and three blocks in a rematch of the
previous Finals as he helped the Celtics beat the
Golden State Warriors in overtime 121–118. On March 2 against the
Cleveland Cavaliers, Horford recorded 23 points, 11 rebounds, and three assists as the Celtics won 117–113.
First NBA Championship (2023–2024) With the arrival of offseason trade acquisition
Kristaps Porziņģis, Horford would assume the role of a reserve, after having started nearly every game up to that point. On April 29, 2024, in Game 4 of the first round of the playoffs against the
Miami Heat, Porziņģis was injured, putting Horford in line to be the Celtics' starting center. On May 15, in Game 5 of the
Eastern Conference Semifinals against the
Cleveland Cavaliers, he recorded 22 points, 15 rebounds, five assists, and three steals in the close-out 113–98 victory, becoming the first player in NBA history to record 10+ rebounds, 5+ three-pointers, 5+ assists, and 3+ blocks. Ten days later, in Game 3 of the
Eastern Conference Finals against the
Indiana Pacers, Horford scored 23 points on a career-high seven three-pointers in a 114–111 comeback victory. The Celtics swept the Pacers in four games and advanced to the
2024 NBA Finals, where he started in all five games as they defeated the
Dallas Mavericks, giving Horford his first NBA championship in his 186th career playoff game, the record for most playoff games before a championship. This made Horford the first Dominican player to win an NBA championship.
Golden State Warriors (2025–present) On October 1, 2025, Horford signed a two-year, $12 million contract with the
Golden State Warriors. ==National team career==