It's rare these days for a star college basketball player to stay in school for more than a year, let alone return to finish a degree after turning pro. But Shaquille O'Neal has made a habit of doing just that.

The 7-foot-1 basketball legend spent three seasons at Louisiana State University before becoming the No. 1 overall pick in the 1992 NBA draft. He left campus without finishing his degree, but he made a promise to his mother that he would one day walk across the commencement stage.

O'Neal has followed through—and then some. He now holds four degrees: a bachelor's, an MBA, an Ed.D., and, most recently, a master's in liberal arts from LSU. “I've always been curious,” he told Fortune. “Basketball was my job, but I never wanted basketball to be the only thing I knew.”

Now O'Neal is back in the classroom once again, pursuing his fifth credential: a master's in criminology at Sacramento State University. It might seem like a surprising use of time for a 54-year-old with an estimated net worth of $500 million, but O'Neal has never lost his appetite for learning.

“Every time I go back to school, I'm challenging myself to learn something new,” he said. “My mother always stressed education, and I've always believed that once you earn that degree, nobody can take it away from you.”

Shaq says it's never too late to keep learning—but Gen Z still has to 'show up' to succeed

O'Neal began the program this summer and plans to complete it in a hybrid format by fall 2027 or summer 2028. He is currently taking a course called “Critical Analysis of Law & Justice.”

His interest in criminology stretches back decades. Beginning in the late 1990s, O'Neal worked part-time with several police departments and even became a reserve officer in both Los Angeles and Miami. Last month, FBI Director Kash Patel named him an honorary FBI special agent.

“I like showing my kids that you're never too old, too successful, or too busy to keep learning,” O'Neal said.

Sacramento State also carries a personal connection: his son, Shaqir, transferred to the university last year to play basketball. The elder O'Neal went on to join the men's basketball program as its general manager in an unpaid, voluntary role, The Athletic reported. That puts him in the unusual position of being an enrolled graduate student and the unpaid general manager of the same men's basketball program at the same time.

O'Neal, who is also currently touring college campuses to teach personal finance, sees college as more than a path to a diploma. To him, it is an opportunity to absorb lessons that extend well beyond the classroom.

“College isn't just about what you learn in a textbook. You learn how to show up. You learn discipline. You learn how to work with people who don't think like you. You learn how to finish what you started,” he said.

At the same time, with AI reshaping the college experience—and the jobs available after graduation—O'Neal acknowledged the growing anxiety many young people face. That tension is playing out across higher education itself: Fortune has reported that some professors are banning ChatGPT from the classroom even as employers look for AI skills in the graduates they hire. He encouraged them to embrace the fact that much of the return on investment in college comes from real-world experience and face-to-face interaction.

“AI can give you information, and I use technology just like everybody else, but it can't replace experience,” O'Neal said. “It can't replace sitting across from somebody who knows more than you and asking questions. To me, that's still valuable.”

From Stephen Curry to Oprah Winfrey, it's never too late to go back to college

While O'Neal is an outlier in pursuing nearly half a dozen degrees, he is not the only person to return to the classroom after reaching fame and success.

Thirteen years after leaving Davidson College to enter the NBA, Stephen Curry completed his bachelor's degree in sociology in 2022. Finishing school was a personal goal.

“Since I left campus, it was a goal to finish,” he said in 2022. “Just as obviously a sense of accomplishment, but a promise I made to my mom and Coach McKillop when I left after my junior year, so it's pretty special.”

Returning to school also gave Curry a new perspective on his career. Through his sociology coursework, he said he was able to examine how athletes use their platforms and financial resources to promote gender equity.

Billionaire Oprah Winfrey also returned to finish what she started. She left Tennessee State University in 1975—just one credit short of graduating—to get a jumpstart on her television career. Years later, in 1987, after she had made her name with her talk show, she turned in her final paper to complete her degree.

For Winfrey, the experience reflected a broader lesson: learning does not end with a diploma, and it does not follow a fixed timeline. Speaking to Stanford graduates in 2008, she encouraged them to treat even their biggest setbacks as opportunities for growth.

“So, ask every failure—this is what I do with every failure, every crisis, every difficult time—I say, what is this here to teach me?”

Overall, she believes success is not a destination reached by a certain age or milestone. As Winfrey said in 2019: “Success is a process.”

This story was originally featured on Fortune.com.