Music, business and cultural icon Shawn "JAY-Z" Carter says he sometimes can't even believe his own success. The mega-mogul rose to fame in the 1990s for his music and went on to become a billionaire through a career that has included numerous record and business deals.

Reflecting on his many endeavors, he said there's one thing that matters to him most: "being a beacon and helping out my culture, people of color."

"I pull the most satisfaction from that," he told "CBS Mornings" co-host Gayle King in an exclusive interview.

Carter has been a vocal advocate for criminal justice reform. Several years ago, he co-founded the Reform Alliance with Philadelphia 76ers co-owner Michael Rubin, New England Patriots owner Robert Kraft and rapper Meek Mill, along with other investors, as a way to help millions of people who are on probation or parole.

He said that while making music was his first love, and something that once consumed him, "the idea of taking that platform and reproducing it for others or doing something like Reform ... I think I derive the most joy from that."

Carter's work is now showcased in "The Book of HOV" exhibit at the Brooklyn Public Library, which offers fans an immersive journey through his life and career. The exhibit's Brooklyn location holds a special meaning for Carter, who was born and raised in the New York City borough. Carter said to him, Brooklyn means "everything."

It was also important for Carter and his team that the exhibit — created by JAY-Z's company Roc Nation — was in a public library, where anyone can see it free of charge. 

One pivotal aspect of the installation is its deep dive into JAY-Z's 13 studio albums. Carter first hit the rap scene as an independent artist before joining Def Jam Records in the early 2000s. 

His debut album, "Reasonable Doubt," holds particular meaning for him. It was released in 1996 by his own record label, Roc-A-Fella Records.

"I needed to grow into this album," he told King. "And had I gone to a label, I don't think I would've been able to fully explore what was really happening, because I had the freedom and the independence to really talk about the real stuff that was happening in the streets, and happening for me and my friends at the time."

JAY-Z also shared a story about another rapper from Brooklyn, The Notorious B.I.G. He says "Streets is Watching" from his album, "In My Lifetime, Vol. 1," was the last song that he played for the late rapper. He said Biggie kept asking him to, "play it again."

But the Grammy Award-winning artist called, "Vol. 2… Hard Knock Life" his "most important album." He said, "it was the album where I honed my craft as a songwriter, and that balance of creating exactly what I want and just as a writer, a technical song-maker, song-making skills with real stories is when it all came together on this album."

The exhibit also showcases one of Carter's business moves: reclaiming his music nearly a decade ago.

It "was the fight of my life, you know, from being an independent company from the beginning. And then going through the Def Jam system, not really understanding how that works. And them having my masters ... then goin' back to Def Jam as the president."

"And then saying, 'Okay, I'll do this job. And part of this job is I have to— my masters has to revert back to me," he said.

Carter said it was important for his children to see his work. He plans to hold the ownership before they go to his three kids, whom he shares with singer Beyoncé.

"You know, if they decide to sell it, then it's up to them," said Carter.

More of Gayle King's conversation with JAY-Z will air Friday on "CBS Mornings."