Johnson continues to sag in popularity despite titles (cont'd)

"I do think there is some growth that is yet to come, because there's just beginning to be the type of appreciation from the general sports fan for what he's accomplished," Levine said. "It's taken a little longer than I would have expected or liked. ... He's separated himself from the other drivers on the track, and he wants to do the same thing off the track."

Johnson's approach to endorsements has never been to take quantity over quality. Lowe's has been a longtime sponsor of his No. 48 car at Hendrick Motorsports and the two are expected to formalize an extension soon, a deal that costs the building supply retailer more than $20 million annually.

HBO Sports' Ross Greenburg

'24/7' with HBO

There may be more correlations between a NASCAR pit crew and an HBO Sports film crew than first meets the eye.

• Real-time documentaries
• 1on1: Ross Greenburg

Johnson is often featured in ads for Lowe's Kobalt Tools brand and he was a central figure in Gatorade's "League of Clutch" campaign two years ago. He also has personal endorsement deals with Tylenol, Sunoco, Gargoyles sunglasses and Bank of America, through its affinity credit-card program The challenge with Johnson, though, is broadening his fan base beyond those who simply appreciate his driving skills and arousing the casual fans enough to make them care about his fourth consecutive title chase.

Mike Mooney, a vice president in Charlotte-based Millsport's racing division, said Johnson's appeal with fans doesn't measure up to his on-track performance. Millsport and its parent company, The Marketing Arm, manage the Davie-Brown Index, which rates Johnson well in awareness but not in appeal. "In a sport where you have so many different personalities, some wear them on their sleeve and some don't," Mooney said. "Jimmie is a very personable guy, but he also comes across as private."

The 24/7 series will give viewers that behind-the-curtain look that will introduce them to a fun-loving, wise-cracking guy, his friends say, which is why the exposure he'll receive from the series could boost his future marketability, while also providing NASCAR with a much-needed jolt of energy.

"The end goal is to show people who Jimmie is and what his lifestyle is about," said John Lewensten, vice president of operations for Jimmie Johnson Racing and the driver's right-hand man. "For the people who really know him, it's hard for us to understand how people think he's vanilla. We've had the media spend time with him away from the track and there have been some articles done, but nothing like this format.

"I'm confident the more people learn about Jimmie, the more they'll become fans. And if the by-product is that Jimmie becomes more marketable in the process, that's great."

24/7 isn't an income producer for Johnson. HBO Sports does not pay either Johnson or NASCAR for its access, although it will pay NASCAR Media Group for its production work.

What the series can do for Johnson, though, is verify what his supporters have been saying all along, that there's more to the greatest winning force in NASCAR than the polite smile he flashes every time he lifts a trophy in Victory Lane.

Ross Greenburg, president of HBO Sports, said the network's documentary-style shows have the ability to change perceptions because of the inside access they receive. That was the case in this year's NFL training camp series Hard Knocks with Cincinnati Bengals receiver Chad Ochocinco.

"Chad is a fun-loving, affable, dedicated athlete and the show blew the doors off the old perception of him," Greenburg said. "That will happen with Jimmie. Characters will come out of this show."