In the hours before kickoff, though, the game's magnitude dawned on him and spawned nerves he hadn't felt in a long time.
On Monday night, Favre became the first quarterback in history to beat all 32 NFL teams _ and the last one sure meant a lot.
Favre's first game against his former team was all fun for the Minnesota Vikings and all frustration for the Packers, as the graying quarterback kept his cool and connected for three touchdown passes and 271 yards in a 30-23 victory.
"I don't know how to explain it. I felt right, but I guess I never thought I'd be in that situation," Favre said.
Favre went 24 for 31, without a turnover.
"Didn't expect him to do that," Packers cornerback Charles Woodson said. "I thought we would play better, but obviously we didn't. And, you know, give him a lot of credit. Played a great game, and apparently he got his wish tonight and stuck it to us pretty good."
Favre celebrated his first scoring toss with an awkward body bump with kicker Ryan Longwell, also a former Packers teammate, and knocked down Chester Taylor on the next one _ showing plenty of emotion on this most emotional night. He stayed poised in the pocket all night, too, and avoided the risky throws that have defined his career almost as much as the success.
"It's why I play the game. It was fun. It never gets old to me, even though I do," Favre said.
The Vikings (4-0) sacked Favre's replacement, Aaron Rodgers, eight times.
Jared Allen was credited with 4 1/2 of them, a career high, including a safety in the fourth quarter that stretched the lead to 16. Rodgers had his first two turnovers of the season, and Favre turned both of them into vintage touchdown passes in the first half.
"I definitely wanted to get this win for Brett," teammate Adrian Peterson said. "It was a big game for him, even though he downplayed it a lot, but you just knew it. You could see it in his eyes."
Favre hugged Rodgers and several other Packers once the game was over.
"I've been saying all along the guy can play. I just wanted to relay that to him," Favre said of his former backup in Green Bay.
Rodgers tried to engineer the kind of drive his predecessor is famous for, but he came up short.
"Below my expectations, definitely," Rodgers said. "To have three possessions where you're in their territory and come away with zero points, two of them are directly related to mistakes by myself, that's disappointing."
Favre enjoyed impeccable protection from his line throughout the game, getting so much time on some throws he could have changed his mind two or three times about whether to play or retire next year.
Rodgers had the exact opposite experience _ often hanging onto the ball too long. He finished 26 for 37 for a career-high 384 yards, many of them in desperation down the stretch, and two touchdown passes.
Rodgers has been sacked 20 times already this season.
"It's obviously an issue that's gone on for four weeks," Packers coach Mike McCarthy said. "You can't play this way. We're playing way too up and down, and it's hurting us."
The Vikings were relentless in their rush, particularly Allen on left tackle Daryn Colledge, who left in the third quarter with a right knee injury. Colledge moved from left guard two weeks ago when Chad Clifton got hurt.
Rodgers' receivers let him down, too, though. On fourth-and-goal at the 1 in the third quarter, Rodgers found tight end Donald Lee open in the end zone. But the ball bounced off Lee's chest and onto the turf, as Rodgers snapped his head back with his hands on the sides of his helmet.
The Packers (2-2) stuffed Peterson with ther new 3-4 defense, holding him to 12 yards on 11 attempts in the second half and 55 yards for the game. They even turned one short gain directly into points: Rookie Clay Matthews joined a gang tackle and ripped the ball out, returning it 42 yards to tie the score at 14.
"I was hoping we'd run the ball better than that," Favre said. "Against a defense like that you don't want to throw the ball that many times. But it was better than I thought it'd be."
One of the most excitable players football has ever seen, Favre's history in emotional games has been mixed. In 2003, on Monday night against Oakland after the death of his father, Favre threw for 399 yards and four touchdowns. In 1999, though, he went 14 for 35 with four interceptions in his first game against Mike Holmgren after the former Packers head coach took over in Seattle.
Favre said he felt on this night a lot like he did in that game after his dad died.
Said Vikings coach Brad Childress: "Some games tickle you a little bit more than others."