Now his reputation is taking a hit, too.
The NFL is investigating the Deadspin website report that he allegedly sent below-the-waist naked photos of himself to a woman who worked for the New York Jets when he played for the team two years ago.
Favre has become one of America's most popular athletes by winning a Super Bowl, setting all kinds of passing and durability records and building an image as an everyday down-to-earth guy.
Just watch one of those Wrangler commercials, where he plays backyard pickup ball with a bunch of smiling and laughing guys while wearing a T-shirt, blue jeans and stubble.
Wrangler, arguably his highest-profile promotion, issued a statement Thursday saying "we are following the story like everyone else.
"We are not making any major decisions on our marketing program until more information is available," Wrangler spokesman Rick French said.
Even if Favre ultimately avoids punishment from the league, it's clear that this damage - fair or not - will be difficult to repair.
"It has certainly shifted to 'good family guy and one of us' to 'just like every other professional athlete' we can't trust," said sports marketing specialist Matt Delzell.
So will we still see Favre starring in television ads after he retires?
"I see it highly unlikely for the simple fact that the companies he endorses have hung their hat on his being a good-old-boy family guy in middle America," Delzell said in an interview from his Dallas-area office, where he's a director for the entertainment marketing agency Davie Brown Talent.
Favre has dodged all questions about the story, even when given opportunities to directly deny it's true. According to marketing and public relations analysts, the Minnesota Vikings quarterback has made the matter worse by not addressing it.
Asked after Minnesota's loss to the New York Jets on Monday night if the allegation has been an embarrassment, Favre said, "I am embarrassed about this football game."
When Tiger Woods tumbled from grace following revelations of his infidelity, he took months to acknowledge his behavior and apologize for it. Michael Gordon, the chief executive officer of Group Gordon, a corporate and crisis public relations outfit in New York, compared Favre's evasiveness on this issue to what happened with Woods.
"It looks like he's trying to dance around it, which is only creating more questions around him rather than fewer," said Gordon, whose firm works with public figures, sports organizations and a variety of others. "If he were more forthcoming it would seem less ominous, but it looks like he's trying to hide something. The people who have handled these situations well are the ones who come out honestly with the facts and tell a complete story so there are no more questions down the road."
Favre doesn't have near the global stature that Woods does, and they also differ in their background.
Part of Favre's attraction to fans was the way he faced up to his past problems and overcame persistent personal tragedies to succeed on the field. His otherworldly performance the day after his dad died of a heart attack was one of the NFL's most memorable games of the past decade.
"Tiger had a very carefully crafted pristine image that at least to the outside made him look like perfect," Gordon said. "With Favre, people are fans of his play but he's never had a perfect reputation."
Favre spent the summer before the 1996 season in a rehab clinic to treat his painkiller addiction, and he has revealed his frequent drinking and carousing early in his career. Both he and his wife, Deanna, have published tell-all books about their ups and downs. They've been married 14 years.
Favre has had his detractors, whether people fed up with his waffling about playing and a perceived egotism behind it or simply Packers backers angry about his signing-with-the-Vikings betrayal. His popularity was widespread, however, transcending his days as a three-time NFL MVP in Green Bay. According to the league, his jersey was the third-best online seller on NFLShop.com over the period from April 1 through Sept. 30.
And according to the business analysts at Forbes.com, Favre made about $7 million last year alone from endorsements. He's done all kinds of advertisements over his career, from credit cards to those famed blue jeans.
Favre also was recently featured by Sears in a spot poking fun at his indecisive tendencies as he pretends to hem and haw over which TV he wants to buy. Spokesman Tom Aiello said the series was intended solely for the 2009 season and that the company is not working with him currently.
Favre's agent, Bus Cook, did not return messages this week.
As much as he's clearly enjoyed the attention and the praise over the years, Favre has also brought a chip-on-his-shoulder kind of defiance to his football career. Asked last year after arriving in Minnesota what his response was to all the people critical of his wavering, Favre shot back, "Don't watch."
But news about the back-and-forth over retirement usually just causes eyes to roll at the worst. Stories like this, even if proved to be false, typically bring far stronger reactions and true backlash.
His Vikings teammates haven't wavered, at least publicly, in their support of him. Asked whether he believes Favre concerns himself with external perceptions at this point in his career, particularly in light of the current scandal, kicker Ryan Longwell shrugged off the potential negative effect on his performance.
"Well, I think we all do to a certain level, but at the same time the public's going to think the way they think and reporters are going to write what they want," said Longwell, who also played alongside Favre with the Packers. "So as much as we do think about it and care about it, ultimately I have to make kicks and he has to play quarterback."