Isaiah Hartenstein ( , ) (born May 5, 1998) is an American-German professional basketball player for the Oklahoma City Thunder of the National Basketball Association (NBA). Listed at , Hartenstein plays the center position.
Before playing in the NBA, Hartenstein played in Germany before playing in Lithuania for Zalgiris Kaunas, with which he won a Lithuanian League championship in 2017. After he left Lithuania in 2017, the Houston Rockets selected him with the 43rd overall pick in the 2017 NBA draft, but he didnâÂÂt make his NBA debut with the Rockets until the next season. In 2024, Hartenstein signed with the Thunder and won the 2025 NBA Finals in his first season with the team. He has also played for the Denver Nuggets, Cleveland Cavaliers, Los Angeles Clippers, New York Knicks, and the Germany men's national basketball team.
Born in Eugene, Oregon, Isaiah Hartenstein is the son of , a basketball coach and former professional player. His mother is a White American, and his father is half African American and half White German. Isaiah's parents met in the United States while his father played basketball at the University of Oregon.
In 2008, Hartenstein and his family moved to Germany, where his father was playing professionally.
Hartenstein joined the MTV GieÃÂen youth ranks and continued his career at the youth teams of QTSV Quakenbrück/Artland Dragons, after his father had signed to play with the Artland Dragons in 2009.
In the 2013âÂÂ14 season, Hartenstein led the Artland Dragons' junior team to a German championship in the Under-16 Bundesliga JBBL, while being named Most Valuable Player. He averaged 20.9 points, 12.1 rebounds, 3.4 assists, 2.9 steals and 1.9 blocks on the season. His father Florian, who served as head coach of the team, was named JBBL Coach of the Year.
Hartenstein was selected to play in the 2014 Jordan Brand Classic International Game: He finished the game with four points and five rebounds in 18 minutes.
On February 1, 2015, 16 year old Hartenstein made his debut in Germany's top-tier level Basketball Bundesliga, seeing 1:12 minutes of action against Eisbären Bremerhaven.
In August 2015, Hartenstein signed a deal with Lithuanian powerhouse à ½algiris Kaunas, but he remained with the Artland Dragons on loan. The Dragons had withdrawn from the Bundesliga, and were relegated to the 2. Bundesliga ProB, Germany's third division. Hartenstein played in 14 games for the Quakenbrück based side during the 2015âÂÂ16 campaign, compiling averages of 11.6 points, 8.9 rebounds, 2.1 blocks, 1.6 steals and 1.4 assists.
In January 2016, Hartenstein decided to leave the Artland Dragons to join à ½algiris Kaunas.
Hartenstein helped the à ½algiris Kaunas Under-18 squad to win the qualifying tournament to the Euroleague Basketball Next Generation Tournament and was selected MVP.
Hartenstein made his debut for à ½algiris in Lithuania's top-flight league, the LKL, on September 28, 2016, against à  iauliai and in the EuroLeague against Fenerbahce on October 26. Later in that season, he helped à ½algiris win the first ever King Mindaugas Cup.
In February 2016, Hartenstein attended the "Basketball Without Borders Global Camp" during the NBA All-Star Weekend in Toronto, Canada. On April 7, 2017, he scored 10 points and grabbed three rebounds in 19 minutes of play at the Nike Hoop Summit.
Hartenstein declared for the 2017 NBA draft on April 22, 2017. He was also named an invite for the 2017 NBA Draft Combine, but he ultimately declined participation for the event. On June 22, 2017, he was selected with the 43rd overall pick in the 2017 NBA draft by the Houston Rockets and subsequently competed for the team in the 2017 NBA Summer League.
In the 2017âÂÂ18 campaign, Hartenstein appeared in 38 games of the NBA G League, averaging 9.5 points and 6.6 rebounds a contest for the Rio Grande Valley Vipers.
On July 25, 2018, the Houston Rockets signed Hartenstein. After being sent down to the Rio Grande Valley Vipers, he was suspended one game without pay after leaving the bench during an altercation in a 132âÂÂ109 loss to the Memphis Hustle on December 17, 2019.
On February 7, 2019, Hartenstein recorded his first career triple-double after posting 12 points, 16 rebounds and 11 assists in a 103âÂÂ102 road win against Salt Lake City Stars. In the 2018âÂÂ19 season, Hartenstein scored 33 points and made a career-high 8 3-pointers in the series-clinching game as they won the NBA G League championship with the Rio Grande Valley Vipers. He won the NBA G League Finals MVP award.
On June 23, 2020, the Houston Rockets announced that they had waived Hartenstein.
On November 30, 2020, the Denver Nuggets announced that they had signed Hartenstein to a multiâÂÂyear contract. Playing behind the All-Star center Nikola JokiÃÂ, Hartenstein averaged 9 minutes, 3.5 points and 2.8 rebounds per game.
On March 25, 2021, Hartenstein and two future second-round picks were traded to the Cleveland Cavaliers in exchange for center JaVale McGee. In his first twelve games with the Cavs, Hartenstein averaged 19 minutes of playing time and 9 points, 7 rebounds, 2.6 assists and 1.4 blocks per game.
On September 27, 2021, Hartenstein signed with the Los Angeles Clippers.
On July 12, 2022, Hartenstein signed a two-year, $16 million contract with the New York Knicks.
On July 6, 2024, Hartenstein signed a three-year, $87 million contract with the Oklahoma City Thunder. On November 20, he made his Thunder debut, putting up 13 points, 14 rebounds, five blocks, and three assists in a 109âÂÂ99 win over the Portland Trail Blazers. Hartenstein made 57 appearances (53 starts) for the Thunder during the 2024âÂÂ25 NBA season, averaging 11.2 points, 10.7 rebounds, and 3.8 assists. In his first season with the Thunder, Hartenstein won his first NBA championship as the team defeated the Indiana Pacers 103âÂÂ91 in Game 7 of the 2025 NBA Finals. He contributed seven points and nine rebounds in the clinching game.
On November 7, 2025, Hartenstein recorded a career-high 33 points, as well as 19 rebounds and three blocks in a 132âÂÂ101 victory over the Sacramento Kings.
Hartenstein represented Germany at the 2014 FIBA Europe Under-16 Championship and the 2015 FIBA Europe Under-18 Championship. He helped carry Germany to a fourth-place finish at the 2016 FIBA Europe Under-18 Championship, averaging team-highs of 14.7 points, 9.5 rebounds, 1.7 blocks, and 1.7 steals a contest, which earned him a spot in the tournament's "All-Star Five".
In August 2017, he made his debut with the German men's national team and took part in EuroBasket 2017, averaging 4.3 points and 2.5 rebounds per game.
|- | style="text-align:left;"| | style="text-align:left;"|Houston | 28 || 0 || 7.9 || .488 || .333 || .786 || 1.7 || .5 || .3 || .4 || 1.9 |- | style="text-align:left;"| | style="text-align:left;"|Houston | 23 || 2 || 11.6 || .657 || .000 || .679 || 3.9 || .8 || .4 || .5 || 4.7 |- | style="text-align:left;" rowspan=2| | style="text-align:left;"|Denver | 30 || 0 || 9.1 || .513 || || .611 || 2.8 || .5 || .4 || .7 || 3.5 |-
| style="text-align:left;"|Cleveland | 16 || 2 || 17.9 || .582 || .333 || .686 || 6.0 || 2.5 || .5 || 1.2 || 8.3 |- | style="text-align:left;"| | style="text-align:left;"|L.A. Clippers | 68 || 0 || 17.9 || .626 || .467 || .689 || 4.9 || 2.4 || .7 || 1.1 || 8.3 |- | style="text-align:left;"| | style="text-align:left;"|New York | 82 || 8 || 19.9 || .535 || .216 || .676 || 6.5 || 1.2 || .6 || .8 || 5.0 |- | style="text-align:left;"| | style="text-align:left;"|New York | 75 || 49 || 25.3 || .644 || .333 || .707 || 8.3 || 2.5 || 1.2 || 1.1 || 7.8 |- |style="text-align:left; background:#afe6ba;"| | style="text-align:left;"|Oklahoma City | 57 || 53 || 27.9 || .581 || .000 || .675 || 10.7 || 3.8 || 0.8 || 1.1 || 11.2 |- class="sortbottom" | style="text-align:center;" colspan="2"|Career | 379 || 114 || 19.5 || .592 || .255 || .686 || 6.4 || 2.0 || .7 || .9 || 6.8
|- | style="text-align:left;"|2019 | style="text-align:left;"|Houston | 2 || 0 || 1.1 || 1.000 || || || .5 || .0 || .0 || .0 || 2.0 |- | style="text-align:left;"|2023 | style="text-align:left;"|New York | 11 || 0 || 20.0 || .478 || || .750 || 4.6 || 1.3 || .8 || 1.4 || 3.1 |- | style="text-align:left;"|2024 | style="text-align:left;"|New York | 13 || 13 || 29.8 || .592 || .500 || .864 || 7.8 || 3.5 || .3 || .9 || 8.5 |- | style="text-align:left; background:#afe6ba;"|2025 | style="text-align:left;"|Oklahoma City | style="background:#cfecec;"|23* || 20 || 22.4 || .619 || || .667 || 7.5 || 2.2 || .8 || .5 || 8.1 |- class="sortbottom" | style="text-align:center;" colspan="2"|Career | 49 || 33 || 23.0 || .600 || .500 || .750 || 6.7 || 2.3 || .7 || .8 || 6.8
|- | style="text-align:left;"|2015âÂÂ16 | style="text-align:left;"|Artland Dragons | ProB | 14 || 24.0 || .479 || .425 || .543 || 8.9 || 1.4 || 1.6 || 2.1 || 11.6 |- | style="text-align:left;"|2016âÂÂ17 | style="text-align:left;"|à ½algiris | LKL | 29 || 12.2 || .490 || .286 || .705 || 3.5 || .7 || .9 || .6 || 4.7 |- class="sortbottom" | style="text-align:center;" colspan="3"|Career | 43 || 18.1 || .485 || .356 || .624 || 6.2 || 1.1 || 1.3 || 1.4 || 8.2