He helped the bank join the just-starting digital revolution.

"Back then a lot of smaller regional banks still did everything on paper," Cuban told Forbes. "Mellon had a department that went in and converted them to computerized systems. That's what I did. A lot of my peers at Mellon were just happy to have a job. I wanted to be more entrepreneurial."

"Some college buddies of mine had told me to come to Dallas — that the weather was great, that there were jobs, and that the women were amazing," Cuban told Forbes.

Dallas would become the base of Cuban's enterprises, from founding companies to bringing a championship to a previously bottom-rung pro sports franchise.

But first he tried his hand at tending bar — and realized that he wasn't that great at working for people.

After striking out as a bartender, Cuban decided to found his first company, a computing consultancy called MicroSolutions.

"I was a PC consultant, and I sold software and did training and configured computers," he told Forbes. "I wrote my own programs. I immersed myself in the PC industry and studied Microsoft and Lotus and watched what the smartest people did to make things work."

A lot of the company's business was in hooking together PCs at small businesses so teams could share information.

MicroSolutions grew quickly. By the time he sold it to CompuServe for $6 million in 1990, it had 85 employees and revenues of $30 million.

The company had an ambitious goal for the mid 1990s: broadcasting radio talk shows, football games, and other forms of streaming audio over the internet.

Started in September 1995 in a spare bedroom in Cuban's apartment, the cofounders were relentless.

"It's nonstop," Cuban told Fast Company in 1998. "Early on, Todd and I asked ourselves a question: What price do you have to pay to win?"

The price, he said, was sprinting all your waking hours.

"You have to build your business faster than anyone else," Cuban says. "The 'sprint' doesn't have a finish line. There's never a point where you can say, 'We've made it.' You have to acquire as much content as you can, and to build as many barriers to entry by others as you can, as fast as possible."

Though AudioNet started as a "sort of radio station for the internet," CNN Money reports that the company soon branched out into video and music retailing, rebranding itself as broadcast.com.

By the time Cuban and Wagner made an inital public offering on July 17, 1998, the site was gathering content from 310 radio stations and 17 TV stations — enough content to provide programming for 24 hours a day.

Wall Street went crazy for it, giving Broadcast.com what was then the biggest first day stock price jump in IPO history. They sold 2.5 million shares, which started trading at $18 per share and rose to $74.

The company's market capitalization went over $1 billion.

He soon became a billionaire.

Making "the billion was, 'I can't f---ing believe it,'" he told James Altucher. "Literally, I was sitting in front of a computer, naked, hitting the refresh because we were close — waiting until my net worth hit that billion when the stock price got to a certain point, and then I kinda screamed and jumped around and then got dressed."

In April 1999, Yahoo! bought Broadcast.com for about $5.7 billion.

"Broadcast.com's tremendous first-to-market advantage has made it the leading destination on the web for audio and video broadcasts, and it will provide significant added value to Yahoo!'s audiences worldwide," said Tim Koogle, Yahoo!'s then chairman and chief executive officer.

It was fortunate timing for Cuban, who sold all his shares before the bubble popped.

Flush with cash, Cuban started making a range of investments, most notably, forking over $285 million on January 4, 2000, to get a majority stake in the Dallas Mavericks, a team that had just completed its 10th losing season in a row.

He'd been a very vocal season ticket holder for years.

Dirk Nowitzki, the Mavs center who would become an NBA star, remembers feeling a little worried that this loud weirdo was buying his team.

"I'm thinking, 'Ohhhh, no! That dude!'" Nowitzki recalled to ESPN a decade later. "I knew right away who it was: the guy from the front row who is always killing Steve when he was subbing in and always had words for the bench. He was like a really involved fan, so I thought, 'This is going to be an experience.'"

The franchise rapidly changed, becoming playoff contenders in the late 2000s and finally bringing home an NBA Championship in 2011.

Having ascended to the top of tech and sports, Cuban's celebrity extended into broadcast television in the late 2000s. In 2008, he was a guest "Shark" on "Shark Tank," the reality pitch show. In 2009, he became a full-time cast member.

He has since made more deals and invested more money than any other Shark. "The show has become a reinforcement of the American Dream," Cuban told D, a Dallas magazine.

The show, now in its sixth season, continues to get top Friday night television ratings, pulling in between 7 million and 8 million viewers a week.

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