In a motorhome parked on the infield of the giant Daytona speedway in Florida sits a part-time racing driver who could well become the most influential man in his sport. Zak Brown is still in his race suit, which does not really fit with the lavish interior of this penthouse on wheels, but his main focus is outside the cockpit.

This weekend Brown is a competitor in the Rolex 24 Hours, the traditional curtain-raiser of the international motor racing season. For just about every other day of the year he is doing deals that shape motor racing worldwide. So successful is he, and so well connected, he might be the man to step into Bernie Ecclestone's shoes when the master of Formula One eventually departs.

Brown, who is still 10 months away from his 40th birthday, was born in Los Angeles and harboured dreams, rare for an American, of being a Formula One driver. He travelled to England and trained at Donington Park under the tutelage of Richard Dean, who became a firm friend and is now a business partner. A penniless Brown spent many nights sleeping on Dean's sister's floor in Sheffield as he tried to work his way up the racing ladder. Like so many who shoot for grand prix stardom he came up short. His struggles to launch and fund his driving career alerted him, however, to the fact that he is one hell of a businessman.

"I didn't go to college," Brown says. "I'm not sure I could even spell it. The business came out of a necessity to make a living because I wasn't making a good living as a driver. The business came about as a need to eat.

"I was told to stop driving – and it hurts your ego at that point – and focus on sponsorship. It was in 1998 when I realised it was not that I wasn't good at finding sponsors, but I wasn't good at finding sponsors for Zak Brown, because Zak Brown wasn't going to take LG or UPS where they need to go. They needed a superstar driver. Once I came to grips with that and started working on sponsorships for other people a light went off and said 'Stop, look at how much business is taking off now.' So I stopped in 2000. Business took off so I was pretty quick to figure out this is where I need to channel 110% of my effort."

That channelling of effort – and it is seemingly limitless — into his company Just Marketing International has made Brown not just a very rich man, but a key figure in Formula One. Last week Brown flew to London for 24 hours and, although he is coy about his business, is believed to have had dinner with Ecclestone, who talks very highly of him.

Members of his 140-strong staff talk of how they never have to wait longer than 20 minutes for a reply to an email, wherever Brown is in the world.

"I don't sleep well," says Brown, "maybe three, four hours a night. I have to clear all my emails before I go to bed and I get 250 a day. But if I roll over and see the red light flashing on my phone I have to see what it is and answer it. It drives my wife crazy when I'm home, which is not a lot."

Is it a bit of an OCD thing? "It's a big OCD thing," he laughs. "I've got problems."

The deals done after those fitful nights have taken LG, UPS and countless other global corporations where they want to go in motor sport. The electronics giant LG is now an official partner of Formula One and their logos adorn Sebastian Vettel's and Mark Webber's Red Bulls. JMI's client list is blue chip and extensive. If you want to get your company into Formula One, Brown is the man who can make it happen, with a solution tailored for every need.

There are parallels with another racing driver who came up just short behind the wheel but still had a massive influence on motor sport. Back in 1958 Ecclestone failed to qualify for the only grand prix he entered and from then on he concentrated on driver management before running a team and then effectively running the sport. Does Brown see the similarity?

"The people who were really successful in motor sports were from the inside," Brown says. "You've got to have a bit of racer instinct in you to survive. Very few people have come from the corporate world, once they have matured in business, and been successful. It's usually someone with a passion for the sport, who started at the grassroots level either as a driver or a mechanic and came up through the ranks. I definitely feel that I'm a racer from that standpoint."

Ecclestone is an admirer of Brown and last year attended the launch of his United Autosports team, an outfit that races a pair of Audi R8s in the British and European GT championships – not the levels of motor sport that the man who runs Formula One's commercial rights normally troubles himself with.

"We've done a lot of business with Bernie," says Brown cheerily. "You'll see us in Singapore, China, Daytona. Sponsorship is the world we live in and we do more of it than anyone else. Yeah, it's a great honour to have someone like Bernie come to our team launch, support our team. I think it says something about the relationship that we have."

Ecclestone was happy to offer a rare endorsement: "I know first-hand the determination and drive Zak Brown delivers to the commercial side of Formula One. Since he brings that same focus and intensity to bear in any enterprise, I'm confident his leadership and marketing skills will be of great advantage to his United Autosports team."

That team goes from strength to strength, racing around the world to increase the brand, often with marquee names behind the wheel. Martin Brundle and Mark Blundell are on the driving strength of Brown's Riley-Ford that, he hopes, will finish well up the leader board when the Daytona race finishes this evening.

What next for Zak Brown? "Brands want big sponsorships and that is what pays big bills when you have 130-140 employees," he says. "You can't feed them off doing $100,000 transactions. We are just going to keep doing what we're doing and just do more of it. Our success is dependent on the sport's success."

The "sport" to many is simply Formula One and with Ecclestone – the commercial rights holder and most powerful man in F1 – now into his ninth decade, there are those in the grand prix paddock wondering what the future holds.

"I think it will be impossible to replace Bernie," says Brown. "You'd certainly have to approach it with a bit of a team. You'd need a chief executive, but Bernie's got such a unique skill set that I look around the world and I don't know if you could pop in and be Bernie overnight. I think that is a concern for the sport because he is 80 so he's not going to go on forever. He's still got a bit of a run in him. I don't think he's going to retire, he's going to go until the lights go off, so he could have another 10 years in him."

The upward curve enjoyed by Brown's business means that he has afforded himself the luxury of racing again on an occasional basis, albeit all around the world and for a team he owns himself. Driving, he says, is the only thing that stops him thinking about his business. But does he see himself, somewhere further up that curve, becoming the most influential man in motor racing?

"That's flattering," he laughs. "Certainly this is my life. I feel that I'm well-rounded, having driven, owned a team, done sponsorship, done business with all these people that have run the sport.

"I would certainly like to be in Formula One, in some capacity, forever. There's a lot I don't know. I've not done television contracts but those things can be learned, or there are other people that have the expertise. I ask for a lot of advice. I have an advisory board of seven individuals with the former president of AT&T and the former CMO of DuPont, so I think one of my strengths has been recognising what I don't know and trying to surround myself with people that do know.

"Every president has his cabinet so I know my limitations and I trip over them every once in a while. I'm not going to charge forward on something I don't have experience in without trying to gather a bunch of experience or getting people around me. I want to be in the sport forever, so if I were ever to get the call to participate in the future of Formula One in some way shape or form, I'd jump all over that."