However, due to practical issues, like a lack of necessary time that was needed to train for both sports properly, he had to choose between the two and finally decided to continue with basketball.

[7] In the 2018–19 season, while competing with Banvit's juniors, Şengün eventually won the Turkish Basketball Youth League championship (which was established in 2017).

[21] On 20 October, Şengün made his NBA debut, putting up 11 points, six rebounds, two assists and three steals in a 124–106 loss to the Minnesota Timberwolves.

[23] After the Rockets traded away Daniel Theis to the Boston Celtics, Şengün's time minutes increased with more offensive strength while remaining a supportive center role for Christian Wood.

On 9 March 2022, Şengün scored 21 points and grabbed 14 rebounds in a 139–130 overtime win against the Los Angeles Lakers.

[26] When the off-season began, the Rockets traded away Christian Wood to the Dallas Mavericks to progress their young roster, giving Şengün an expectation to take the role in the starting lineup for the center position.

On 11 January 2023, Şengün put up his first career triple-double with 10 points, 10 rebounds and 10 assists in a 135–115 loss to the Sacramento Kings.

[33] On 16 January, he put up a career-high 33 points along with 15 rebounds, six assists and four blocks in a 140–132 loss to the Los Angeles Lakers.

[35] On 25 January, he recorded his second career triple-double with 21 points, 11 rebounds and 10 assists in a 108–103 loss to the Washington Wizards.

[36] Şengün grabbed a season career high of 21 rebounds with 14 points in a game win against the Charlotte Hornets on 7 April.

Kevin Durant was asked on which young players he really enjoys watching play: "I would say I was going to give some love to Alperen Şengün.

"[38] and Los Angeles Clippers forward Paul George compared Şengün's passing and rebound playmaking to Magic Johnson, Pau Gasol and Jokić.

[46] On 20 January 2024, Şengün tied his then-career high with 37 points, along with 14 rebounds and six assists in a 127–126 overtime win over the Utah Jazz.

[48] On 24 January, Şengün and teammate Jalen Green became the first duo in NBA history to score 30-plus points and 10-plus rebounds at 21 years or younger in a 135–119 win against the Los Angeles Lakers.

[49] On 5 March, Şengün put up a career-high 45 points and 16 rebounds in a 114–101 win over the San Antonio Spurs while being guarded by rookie Victor Wembanyama.

[53] On 6 March, Şengün put up his second triple-double of the season with 23 points, 19 rebounds and a career-high 14 assists, becoming the first center in NBA history to achieve those numbers in a game from a 122–116 loss to the Los Angeles Clippers.

You’re not going to continue to miss those.”[60] After a slow start to the season, Şengün recorded back-to-back triple-doubles in blowout wins against the Los Angeles Clippers and Chicago Bulls.

[62] After defeating the Atlanta Hawks in a victorious 100-96 lead, Şengün became the 16th player in NBA history to have recorded at least 4,000 points, 2,000 rebounds, and 1,000 assists playing around 250+ games and became the fifth player to have reached 4000+ points, 2000+ rebounds and 1000+ assists along with 250 steals and 200 blocks through that many games, joining Alvan Adams, Larry Bird, Lionel Simmons and Chris Webber.

[64] On February 4, Şengün returned from a three-game absence due to a left calf contusion and recorded 24 points, 20 rebounds and four assists in a 99–97 loss against the Brooklyn Nets.

[65] Şengün competed with the Turkish under-16 national team at the 2018 FIBA Under-16 European Championship, which was held in Novi Sad, Serbia, where he finished the competition by winning the bronze medal.

[68] Şengün also played at the 2019 FIBA Under-18 European Championship, with the Turkish under-18 national team, which won the tournament's silver medal.

[70] In November 2020, Şengün joined the senior Turkish national team, as he played with Turkey at the 2022 EuroBasket Qualifiers.

[73] Standing at 6 feet 11 inches (2.11 metres) and 243 pounds (110 kilograms) with a seven-foot (2.13 m) wingspan, Şengün plays at the power forward and center position.

[74][75][76] With a solid frame and wide base, he is known for a versatile and highly efficient low-post game that utilizes drop steps, spin moves and fadeaways.

[78][79] As a defender, he is most effective on on-ball matchups in isolation against other big men, though his defense in general has been called into question.