Unlike many National Football League owners, Robert Kraft wasn't born into the league, nor was he born into the billions he has now.

What the owner of the New England Patriots does have is a lifelong connection to the team he now owns. Kraft was born in 1941 in Brookline, Mass., to a working-class family. He went to high school there, decamped for New York's Columbia University for his undergraduate degree, and returned to get his MBA at Harvard in 1965.

Kraft became a Patriots season ticket holder in 1971, surely having no idea that 23 years later, in 1994, he would purchase the team. Owning the Patriots helped build Kraft's fortune, but when he made the move to do it, he was taking a huge risk.

It was a gamble that of course ultimately paid off, making a man who had been successful in business incredibly wealthy. Kraft has been good for the Patriots, but the team has also been good for its owner.

The Patriots were terrible
Before Kraft, the Patriots had a long, mostly miserable history. There was a lone Super Bowl appearance in 1986, when the team was trounced by a legendary Chicago Bears team. Aside from that, the team was mostly a laughingstock.

Kraft's journey to owning the team began in 1985, when he took an option on the land surrounding where the team played its home games in Foxborough, Mass. In 1988 he added the stadium to his portfolio, buying the then-Sullivan Stadium for $25 million, according to Forbes.

Built in 1971, the home of the Patriots was a rundown place lacking any amenities. It didn't even have seats. Fans sat on frigid metal benches, which were as unpleasant as you might imagine during the long winter months.

Sullivan had almost nothing going for it, except a contract for the Patriots to play there through 2001. In attempting to buy out that lease to move the team to St. Louis, then-owner James Orthwien offered Kraft $75 million. That would be an amazing return on the money spent buying the stadium. 

Instead of taking it, Kraft countered by offering $175 million to buy the team. That was a stunning amount to pay for a losing franchise playing in a stadium more likely to be condemned than host a playoff game, but it proved to be the best move Kraft would ever make when it came to his personal fortune.

Source: New England Patriots Twitter feed.

What is Robert Kraft's net worth?
Even a casual football fan knows what happened next. Kraft gets to a Super Bowl in 1996 with Bill Parcells as his head coach, and Parcells quits following the season. That led to the hiring of Bill Belichick, the inexplicable rise of the team's sixth-round draft pick in 1999, Tom Brady, six more Super Bowl appearances, and four wins.

Along the way, Sullivan Stadium was replaced with the state-of-the-art Gillette Stadium, and what was once one of the least valuable teams in the NFL has become the sixth most valuable team globally in all of sports, according to Forbes' 2015 list. The Patriots are not the only source of wealth Kraft has, but the team alone is worth $2.6 billion.

Kraft also owns Major League Soccer's New England Revolution, which also plays at Gillette, and he retains the paper manufacturing business that produced the money that allowed him to buy the Patriots in the first place.

That company, the Kraft Group, has $2.7 billion in sales annually, according to Forbes, which estimates Kraft's total net worth at $4.3 billion. That makes him the 125th richest person in the United States, and the one with the most Super Bowl rings.

Daniel Kline is a lifelong Patriots fan. His brother is chief revenue office for the Miami Dolphins. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.