He proved that by having possibly his best statistical season as he crossed age 40.
His conduct off the field, however, has left a lot to be desired. He orchestrated his departure from Green Bay with some rather nefarious and manipulative behavior, then did even worse to the New York Jets, paving the way for his arrival in Minnesota.
Instead of deciding to play football and talk the Vikings into letting him skip the portion of training camp that takes place in Mankato, he has lied to the world about his intentions the last two summers.
In Monday's Minneapolis Star Tribune, Vikings writer Judd Zulgad threw out a few ideas as to why Brett seems to insist on taking this route, rather than just being upfront about what he wants to do.
Favre's wavering has become part of his legend and marketability. The Packers eventually tired of this dance and moved on with Aaron Rodgers, but the Vikings are willing to wait and bank on the belief that Favre isn't going to pull the plug on his career.
... Yes, Favre seems to have concerns about his surgically repaired left ankle, but this wasn't a major procedure, it was essentially a clean-up job. Last year, Favre went through the same thing as he vacillated after having surgery on his throwing shoulder to repair a torn biceps.
The real question is whether Favre even believes what he's trying to sell to the public -- and his employer. Some will say that he truly is filled with doubt. The cynic will call this all part of his offseason act: an attempt to stay away from camp as long as possible and ride in on his white horse at a more convenient time.
So which is it?
In a lengthy story in Men's Journal on Favre that hit newsstands Friday, the quarterback admits that recapturing the success of 2009 won't be easy.
The Vikings' schedule appears far more difficult, and there are no guarantees the breaks again will go the team's way. The last-second touchdown pass on which Greg Lewis made a remarkable catch against San Francisco and the missed field goal by Baltimore with 2 seconds left come to mind as examples of games that could have gone the other way.
"What are the odds that I have another season like that, even if I play well?" Favre asked.
These are all valid points. People have sometimes mistaken Brett for a bit of a hayseed -- kind of part of his image, in a weird way -- over the years, but he's far from it.
Favre is a shrewd, intelligent man who understands football and understands his place among the legends in the game. He also loves the attention his annual dance with retirement has brought him. He enjoys the cameras buzzing around the high school where he has spent time the last two summers getting his arm into shape. He likes hearing reporters talking about him on television, and he likes it when people probe him for information.
He knows he's playing in 2010, and the Vikings know he's playing in 2010. By playing up the indecision, he's able to justify skipping the team's offseason workouts and the portion of training camp that takes place in Mankato. The Vikings' training camp home is a city about an hour southwest of the Twin Cities that swells when camp comes along, but would burst with throngs of fans and media if they knew Favre was going to be there.
The circus you saw last August when he showed up at Winter Park was bad enough, but the Twin Cities are more than big enough to handle it. Mankato is probably better off without it, in a way.
More than anything, Favre doesn't have to worry about his teammates holding against him the fact that he gets to skip camp. After all, he hasn't made up his mind, and no one is supposed to know any different.
Oh, and he threw for over 4,000 yards and 33 touchdowns to just seven picks last year. That came after he skipped training camp. Good luck telling him he shouldn't walk the same path again, even if there's plenty of evidence that it's not the best idea.