In November of 1977, Jake Steinfeld, a freshman lacrosse player at the State University of New York at Cortland, was standing on a field in the hail. “What am I doing?” he wondered. It was freezing, and he saw no future in the sport. So Steinfeld — a weightlifting enthusiast since age 13 — dropped out, moved to Northridge, Calif., and became a bodybuilder.
After winning a few small competitions, he moved over to Studio City and fell into a routine: lifting weights in the morning, working as a bouncer at night. Sandra Will, an actress, approached him one day and told him she needed someone to help her get in shape for a commercial. He trained her, she told friends about his services, and word spread. Among many other big names, Steinfeld worked with Steven Spielberg — who later hired him to help Harrison Ford train to play Indiana Jones — and named his company Body By Jake. He offered personal training by appointment, exercise videos, and eventually TV spots.
Steinfeld milked his Hollywood connections, grew the business, and in 1993 launched a 24-hour network, FitTV, with Tim Robertson, son of televangelist Pat. In 1998, Steinfeld sold FitTV to News Corp. (NWSA) for an undisclosed figure. He had money, recognizable celebrity, and an itch to try a new venture. His mind returned to those freezing lacrosse practices.
He had read about Dave Morrow, an All-American lacrosse player who founded Warrior, a lacrosse equipment and apparel maker. On a whim Steinfeld called Morrow to persuade him to create a professional lacrosse league. No such thing existed. “He just called me out of the blue,” Morrow says. “It was a 310 number so I thought it was one of my old teammates messing with me. When I called back, someone answered and said, ‘This is Craig from Body By Jake,’ and I almost hung up the phone.” Morrow didn’t, and within minutes the gregarious Body By Jake guy had convinced him.
The two former laxers, along with Robertson, funded Major League Lacrosse (MLL) by themselves. But by the end of the first season, in 2000, MLL was out of money, Steinfeld says. The trio scrounged for years. A turning point came in 2004: Morrow sold Warrior to New Balance, and its owner, Jim Davis, bought a controlling stake in the league, saving it.
Today, the league has just wrapped up its 12th season, with its championship match played on August 26 at Harvard Stadium in Boston. While the MLL is growing nicely, many American sports fans still aren’t aware that pro lacrosse even exists. Dave Gross, MLL commissioner, says that’s to be expected — it seems that creating a sports league from scratch is not easy. “We are not going to be an overnight success,” he says, “but nothing in sports happens that way. We’re not the NFL; we’re not even the MLS at this point. But we’re growing it in the right way.”
Mike Stone, a midfielder for the Boston Cannons (2011 champions), says recognition isn’t why the players are in it anyway. “Right now, with the state of the MLL, you’re doing this because you love the sport,” he says. “We all know nobody is making a killing at it, and it’s a grind for everybody.” Indeed, pros make only $13,000, on average, per season; thus they all have regular jobs. The season is short — 13 weeks — and falls in summer. Still, guys like Stone get paid to do what they love, all thanks to Steinfeld, whose name graces the playoffs trophy.
The Body By Jake boss is now focusing his time on beefing up the league’s size and reach: He helped launch the program Inside the MLL, which began airing this season on CBS Sports Network. He has people working on technology that will make it easier for a casual fan to watch the sport. TV footage will now highlight the player who has the ball, much like in video games, and akin to what Fox tried to do with pro hockey when it highlighted the zooming puck in the late 90s.
The MLL has sponsorship deals with beverage bigs like Powerade, Coke Zero, and Bud Light. This year two expansion teams debuted: the Charlotte Hounds and the Ohio Machine. The latter, in a June game against the Denver Outlaws, pulled a crowd of 30,128, the biggest in MLL history. And it will continue to expand: The MLL plans to add two more teams in Florida, Texas, or Atlanta by 2014. After that, it’s shooting for four new teams on the West Coast, which would bring the total to 14.
“We’re getting close,” Steinfeld hopes, “to the tipping point.” And Hollywood still beckons: Lionsgate bought Take a Shot!, a book by Steinfeld and Morrow about creating the league, with plans to make it into a TV Drama series.
On starting a company
Dive in. “Don’t get ready, don’t get set. Just go,” Steinfeld says on starting his league. “Sometimes the smartest people are the most paralyzed.”
Find people you trust. “People you know will always have your back, not when you’re standing on top of the mountain but in the deepest ditch.”
Constantly adapt. “Keep reinventing yourself; that’s the only way you survive. Also, it’s important for your sanity.”
A shorter version of this story originally appeared in the September 24, 2012 issue of Fortune.