It wasn’t that long ago that Oklahoma City Thunder center Isaiah Hartenstein found solace in a psychology book to help him cope with the stress and reality of being an NBA journeyman. Reality now includes stability for the big man and the ability to take a sigh a relief after signing a $87 million contract following six challenging NBA seasons.

But knowing the struggle quite well, all that money won’t allow him to relax the survival mentality that has brought him so far.

“At the moment I signed the contract, it was special,” Hartenstein told Andscape recently. “Just grinding through the NBA. Going from the G League with the [Houston] Rockets and being sent back down consistently kind of proving myself. It was never easy. It wasn’t like a relief, but it was an excitement.

“I didn’t feel like I could let off the gas. The hard work finally paid off even if it was a little longer than I thought it would take. I was excited yet motivated at the same time that I had proven myself.”

Hartenstein played for the Houston Rockets, Denver Nuggets, Cleveland Cavaliers, LA Clippers and New York Knicks from 2018 to 2024. The 7-foot, 250-pounder also spent time early in his NBA career playing in the G League for the Rio Grande Vipers. In a June 23, 2020, Rockets news release announcing the signing of David Nwaba, the team stated simply at the end: “In a related move, the Rockets have waived center Isaiah Hartenstein. He was the 43rd pick by Houston in the 2017 NBA draft and appeared in a total of 51 games as a Rocket.” No other statistics were included.

On Nov. 30, 2020, the Nuggets signed Hartenstein to a two-year, $3.3 million contract to serve as a backup to All-Star center Nikola Jokić. Hartenstein’s father, former Oregon center Florian, spent time in Denver with his son to offer support, take him through basketball workouts and even cook meals. Being in the midst of the coronavirus pandemic added to the stress as well.

“In general, it was hard playing behind Jokić at about eight minutes a game,” Hartenstein said. “It wasn’t going great. Denver was probably the hardest time. It was after COVID and that was the first time where I felt maybe it won’t work out. But I just kept going on.”

Hartenstein has always been a voracious reader. Hoping to help himself mentally on and off the floor, he searched online for sports psychology books that could give him guidance. He found The Mindful Athlete: Secrets to Pure Performance by George Mumford. NBA legend Michael Jordan once credited Mumford with helping him become a better leader. Mumford also aided former Los Angeles Lakers stars such as Shaquille O’Neal, Lamar Odom and Kobe Bryant.

Mumford, who roomed with Julius Erving at UMass, is a widely respected public speaker and coach who shares his story, strategies and proven techniques to help aid athletic performance in the popular book. Hartenstein credited The Mindful Athlete for helping turn his NBA career around in Denver by getting him deeper in “mental space and mental preparation.”

“It figured it out for me. I was in a state where I needed to work [on my mentality] more and it worked from there,” Hartenstein said of The Mindful Athlete. “The main thing it taught me was staying present, being more process-driven.

“There are going to be ups and downs, but don’t get too high or too low. You’re going to have some bad games. Don’t let it linger on. Get on to the next thing. Control what you can control.”

Hartenstein played sparingly for the Nuggets before being traded to the Cavaliers on March 25, 2021. He showed signs of being a proven NBA player with the Cavaliers, averaging 8.3 points, 6.0 rebounds and 1.2 blocks in 16 games during the 2020-21 season. He next signed with the Clippers on Sept. 13, 2021, despite it being a one-year, minimum contract. Hartenstein made the Clippers and averaged 8.3 points and 4.9 rebounds off the bench in 17.9 minutes in 68 contests during the 2021-22 season.

Hartenstein believes his time with the Clippers proved that he was an NBA center.

“That was the first season where I was consistently in the rotation,” Hartenstein said. “I had good months with the Rockets, but Clippers was the most consistent [season].”

The NBA nomad was rewarded with his first contract with an annual salary over $2 million by inking a two-year, $16 million contract with the Knicks on July 1, 2022. He averaged 6.3 points and 7.4 rebounds per game in 157 games with the Knicks from 2022-24. Most notably, Hartenstein was a successful starting center for New York in the regular season and playoffs after Mitchell Robinson was injured.

Hartenstein felt respected and beloved in a Knicks uniform and loved playing in Madison Square Garden.

“It was big playing in the Mecca [Madison Square Garden], playing in big games, especially the playoffs,” Hartenstein said. “Me and Jalen [Brunson] came in there and kind of changed it around. That was big. Playing in the Garden was always special. Being out there was a special experience.”

Hartenstein’s father is Black and German and his mother is a white German. He told Andscape in 2017 that he’s proud of his Black roots and his father taught him African American history. Hartenstein, who is of a lighter skin tone, said he dealt with racism during his youth in Germany and has confronted people, who didn’t know he was a Black man, who made racist comments about Black people in front of him.

He also discussed being Black on the podcast, The Roommates Show, hosted by Brunson and Josh Hart, who were then his teammates on the Knicks.

“It was funny,” Hartenstein said of the podcast. “I knew they were doing it. They were talking about it the whole week [before].”

He added, “[Andscape] was the first to release it to the world. It is always funny when people find it out.”

The Knicks wanted to retain Hartenstein and offered him a four-year, $72.5 million deal. Hartenstein, however, opted to sign a more lucrative three-year, $87 million deal to join NBA All-Star guard Shai Gilgeous-Alexander and the rising Thunder on July 6. Hartenstein had previously earned a combined $22.6 million in earnings in his NBA career. He is making $30 million this season.

Looking back, Hartenstein is very proud of what he was able to accomplish after a slow start to his career.

“It was hard to leave. It wasn’t easy. I loved being out there and I loved my teammates,” Hartenstein said of New York. “If I couldn’t go to a place like OKC, I don’t think I would have left. But you also have to think about it being a business at the end of the day. It wasn’t like I’ve had a whole bunch of $100 million contracts before this. I had to make sure my family was straight.

“It was a crazy experience going from a minimum deals and training camp deal with the Clippers. Going from that to this, it’s a good little journey. A lot of times you don’t get what you’re going through. But now looking back, I wouldn’t change a thing on and off the court.”

Hartenstein’s challenging NBA days returned when the Thunder announced that he suffered a small, non-displaced fracture in his left hand on Oct. 15 in a preseason game against Denver. The good news was the injury did not require surgery, but Hartenstein’s debut with the Thunder was delayed.

After learning about Hartenstein’s love of reading, Thunder coach Mark Daigneault gave him the book The Obstacle is the Way: The Timeless Art of Turning Trials Into Triumph by Ryan Holiday. The Wall Street Journal No. 1 bestseller is inspired by stoicism, the ancient Greek philosophy of enduring pain and overcoming adversity with perseverance and resilience.

“He talks about his time in Denver when he really worked on his mental game,” Daigneault told Andscape. “I recommended that book because he had gotten hurt. But it is kind of in his wheelhouse. He is a very intelligent guy.”

“Mark gave me the book and it helped a lot going through the process of [the injury]. Just reading that and going through the process of every obstacle and not wasting time,” Hartenstein said.

Hartenstein was given a hero’s welcome by the Thunder fans when he debuted with 13 points and 14 rebounds in a 109-99 win against the Portland Trail Blazers on Nov. 20. He is averaging career highs in points (13.3), rebounds (12.3), assists (4.2) and blocks (1.5) through six contests for the Thunder, who at 16-5 have the best record in the Western Conference entering Wednesday.

“He is obviously big, and we had a smaller and outrebounded team last [season],” Daigneault said. “That is like the A-B explanation [for signing him]. But that doesn’t do it justice for how good of a player he is. He’s not just a big body who can rebound. He’s a great basketball player.

“He’s great at the most relevant things on the basketball floor. He’s a complete glue guy that enhances both sides of the floor because of how dynamic he is.”

For NBA players struggling early in their careers, Hartenstein believes they can find inspiration in his story.

“Just be process-driven,” Hartenstein said. “Sometimes it takes time. We all go into the NBA wanting to play right away. Mentally you have to be strong and don’t be a negative. A lot of guys early on don’t play and they’re not good locker room guys. They don’t support their teammates when you don’t get your chance.

“You have to stick around until you get your chance. Do the little stuff. Be a good teammate. And just be ready when your time comes.”