Born in Paris to Malian and Guinean parents, Diabaté started playing basketball at age 12 with Sporting Club Maccabi de Paris.[2][3] After a few months, he moved to USD Charonne, where his interest in the sport formed, and he later competed for Saint Charles de Charenton Saint Maurice. Diabaté was not allowed into the sports institute CREPS for academic reasons. At age 14, he moved to the United States to advance his basketball career. In eighth grade, he joined the middle school program of Montverde Academy in Montverde, Florida. At first, he did not speak English and struggled to adjust to the American style of play.[2]
On 20 February 2022, Diabaté was involved in the postgame melee following a 77–63 loss to Wisconsin and appeared to throw punches. He was suspended one game by the Big Ten Conference for his role in the brawl.[14] Diabaté was named to the Big Ten All-Freshman Team.[15] He averaged 9.0 points and 6.0 rebounds in his freshman season. On 25 April 2022, he declared for the 2022 NBA draft while maintaining his college eligibility.[16] However, on 1 June 2022, Diabaté announced he would remain in the draft and forego his remaining eligibility.[17]
On October 22, 2022, Diabaté dressed for the second game of the season for the 2022–23 Los Angeles Clippers but did not play.[22][23] The second time he dressed, he played in the team's 5th game on October 27, for 1:47 accumulating an assist, steal, 2 rebounds, a field goal and a free throw against the Sacramento Kings.[24][23] On December 14, he was named G League Player of the Week for a pair of 20-point/20-rebound efforts.[25] On December 17, in his 8th NBA game, with Paul George, Ivica Zubac, Reggie Jackson and Norman Powell unable to play, he made his first start at home against the Washington Wizards.[26][23] Following the season, he was named to the G League's All-Rookie team.[27] He was also named to the postseason All-NBA G League Team third team.[28]
On July 14, 2023, Diabaté signed another two-way contract with the Clippers.[29]
Diabaté led France to fourth place at the 2018 FIBA U16 European Championship in Novi Sad, Serbia. He averaged 11.1 points and 10.3 rebounds per game, recording 16 points and 17 rebounds against Serbia in the quarterfinals. At the 2019 FIBA U18 European Championship in Volos, Greece, he averaged 13.1 points, 11.1 rebounds and 2.1 blocks per game for France, who came in fifth place. In a group stage win over Greece, Diabaté recorded 14 points and 20 rebounds.[31]