Mark Cuban always tries to push himself out of his comfort zone, so it's no surprise that he does the same for others.

Cynt Marshall, CEO of the Dallas Mavericks, experienced it firsthand when Cuban cold-called her with a job offer in 2018, she recently told LinkedIn's The Path newsletter. Marshall, 63, had left her job as chief diversity officer and senior vice president of human resources at AT&T, and was running her own consulting firm at the time.

She had ample leadership experience, and was an expert in workplace positivity and inclusivity, which the Mavericks needed at the time — following allegations of harassment and a toxic workplace culture, as reported by Sports Illustrated earlier that year.

But there were two problems. First, Marshall didn't know who Cuban even was. Second, she said: "I was well aware of the fact that I did not know the business of basketball."

In response, Cuban gave Marshall some simple yet effective advice, she recounted: "He said, 'You don't worry about that. I will teach you the business side of basketball, and others will do the same.'"

This reassurance, and some extra convincing, prompted Marshall to accept the job, becoming the first female CEO in the NBA and the first Black woman to lead an NBA team. "I thought twice about it because I was loving what I was doing with consulting, but here was an opportunity to serve ... to have an impact," she said.

Prior to her appointment, the Mavericks had no women or people of color in leadership, LinkedIn noted. Within two years of Marshall's appointment, 50% were women and 47% were people of color, a Mavericks spokesperson told CNBC Make It in 2020.

It's part of why Cuban says choosing Marshall was a no-brainer. "She is amazing, forceful, dynamic, nurturing," he told CNBC Make It.

For Marshall's part, she's still learning even today, she told LinkedIn.

"Some of the gaps still exist. I will never know what some of these people know about the business of basketball," she said. "But I don't need to know it. I learn from it every day. What I need to do is lead these people, learn from these people and love these people, and I try to do that every day."

And as for the guarantee Cuban made during the cold call? "I love my boss," Marshall said. "He kept his promise."

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