Anadolu Efes (2011–2017) In 2007, Osman signed a youth team contract with
Anadolu Efes after his outstanding performance at KK Bosna. He played for the junior, star, and youth teams of Anadolu Efes. He was
loaned for the 2011–12 season to the Pertevniyal of the
Turkish Basketball First League, which was at the time the
farm team of Anadolu Efes. In the summer of 2012, Osman signed a professional contract with the Anadolu Efes senior team.
Cleveland Cavaliers (2017–2023) during a game in 2021 On 25 June 2015, Osman was selected with the 31st overall pick in the
2015 NBA draft, by the
Minnesota Timberwolves. His draft rights, along with those of
Rakeem Christmas and a future draft pick, were then traded to the
Cleveland Cavaliers, in exchange for the draft rights to
Tyus Jones that same night. On 18 July 2017, Osman signed with the Cleveland Cavaliers. On 9 February 2018, Osman played 38 minutes in a 123-107 Cavaliers victory over the
Atlanta Hawks. He contributed 16 points on 6-of-9 shooting while notching 6 rebounds, 5 assists, and 3 steals. The Cavaliers made it to the
2018 NBA Finals, but lost 4–0 to the
Golden State Warriors. On 25 January 2019, in a 100–94 loss to the
Miami Heat, Osman scored a career-high 29 points. Four days later, Osman was named a participant for the 2019
Rising Stars Challenge as a member of the World Team. On 26 October 2019 Osman signed a contract extension with the Cavaliers. On 22 March 2022 Osman recorded his 500th 3 pointer as a member of the Cavaliers. This made him just the 9th Cavaliers player ever to join the 500+ 3 point club.
San Antonio Spurs (2023–2024) On 6 July 2023 Osman was traded to the
San Antonio Spurs as part of a three-team trade with the
Miami Heat and
Cleveland Cavaliers.
Panathinaikos (2024–present) On 7 September 2024 Osman signed a one-year deal with the reigning
EuroLeague and
Greek League champions
Panathinaikos. On 9 April 2025, Osman agreed upon a two-year contract extension with the defending EuroLeague champions, worth 3.3 million euros. On April 15 of the same year, the deal was made official. On May 6, 2025, Osman was the deciding player in Panathinaikos' quarterfinal game 5 75-67 win over
Anadolu Efes, scoring 28 points, more than a third of his team's total tally, and collected 8 rebounds. On March 14, 2026, he was named the Most Valuable Player for Round 31 of the 2025-2026 EuroLeague Regular Season. He had 24 points, 5 rebounds, 3 assists, and 2 steals. ==National team career==