"I know I can still play, but it's like I told my wife, I'm just tired mentally. I'm just tired," Favre, a 17-year veteran and three-time NFL MVP, told ESPN's Chris Mortensen in a voice mail message.
"If I felt like coming back -- and Deanna [his wife] and I talked about this -- the only way for me to be successful would be to win a Super Bowl. To go to the Super Bowl and lose, would almost be worse than anything else. Anything less than a Super Bowl win would be unsuccessful," Favre said in the message.
"I know it shouldn't feel unsuccessful, but the only way to come back and make that be the right decision would be to come back and win a Super Bowl. And honestly, the odds of that, they're tough. Those are big shoes for me to fill, and I guess it was a challenge I wasn't up for. "
Packers coach Mike McCarthy told Mortensen that Favre called him Monday night to tell him his decision. He also said Favre had first mentioned the possibility of retiring on Thursday.
"He called me last night to tell me he'd thought this thing through and he said, 'Well, you know how it is,' and 'I'm just tired and I just think it's time,' " McCarthy said.
"And I did tell him last Thursday when he mentioned retirement for the first time, I told him while we talked that he did have to trust his heart."
The news was a surprise to at least one of Favre's teammates. Most players expected Favre to return after a successful 2007 season.
"I just saw it come across the TV," Packers wide receiver Koren Robinson said, when reached on his cell phone by The Associated Press.
Favre, 38, had made his annual flirtation with retirement a winter tradition in Wisconsin. He has taken weeks and even months to make his decision after recent seasons, with Cheeseheads hanging on his every word.
But unlike the final game of the 2006 season -- when Favre provided a cliffhanger by getting choked up in a television interview as he walked off the field in Chicago, only to return once again -- nearly everyone assumed he would be back.
A sure-fire first-ballot Hall of Famer, Favre put the Packers back among the NFL's elite. He retires with 5,377 career completions in 8,758 attempts for 61,655 yards, 442 touchdowns and 288 interceptions, passing Dan Marino's touchdown mark last season.
As a player Favre was known for his durability, his willingness to take risks and turn broken plays into big gains, as his love for the game that was evident in the way he played. He led the Packers to Super Bowls in 1996 and 1997, winning it all on his first try in Super Bowl XXXI, and was named to nine Pro Bowls.
In Super Bowl XXXI, a win over the New England Patriots, Favre went 14 of 27 for 246 yards and two touchdowns. A year later, in Super Bowl XXXII, he went 25 of 42 for 256 yards, three TDS and an interception in a loss to the Denver Broncos.
He finished his career on a streak of 253 consecutive regular season starts -- 275 including playoff games.
Favre's agent, Bus Cook, told Mortensen that as of Tuesday morning, there were no plans for Favre to hold a news conference.
"I talked to Brett this morning and I told him, 'nobody forced you to make this decision to retire, but the flip side is nobody encouraged you to play,' " Cook told Mortensen. "Two years ago, Ted [Thompson, the Packers' GM] encouraged him to play, but there was nothing this time around from them offering encouragement or him to come back."
The Packers said they would hold a news conference at 4 p.m. ET on Tuesday.
"He has had one of the greatest careers in the history of the National Football League, and he is able to walk away from the game on his own terms. Not many players are able to do that," Thompson said. "The Packers owe him a tremendous debt of gratitude. He has given Packers fans 16 years of wonderful memories, a Super Bowl championship among them, that will live on forever."
Former Packers GM Ron Wolf, who engineered the trade that brought Favre to Lambeau Field, told ESPN Radio's Colin Cowherd that Favre was the best player he ever saw.
"I was in the game 41 years and was around an awful lot of great players, but the greatest player I was ever around was Brett Favre," Wolf said.
Wolf was surprised by Favre's announcement, but felt it was the right choice.
"The way he played and the style he played and how he played requires an awful lot of dedication and passion, and if he no longer has the passion to play, then it's very, very wise for him to hang 'em up," he said.
Favre, who returned for the 2007 season when many thought he should have left the game, had a career renaissance in his final season and led Green Bay to the NFC Championship Game, where the Packers lost to the eventual Super Bowl champion New York Giants in overtime.
Favre passed Marino for the all-time completions record in 2006, and in 2007 set NFL records for wins by a QB, touchdown passes, pass attempts, passing yards and interceptions. He claimed the NFL record for career quarterback wins with his 149th victory in Week 2, passed Marino for the TD record in Week 4 and overtook Marino's career passing yards record in Week 15.
Mortensen reported that Favre, who wanted the Packers to obtain Randy Moss when he was a free agent last season, had once again pushed for Moss to join the Packers.
Favre had spoken to Moss late last week and was willing to commit to more than just this season if Moss and the Packers could come to an agreement. But the Packers did not pursue Moss, who re-signed with the Patriots on Monday.
In his voice mail message to Mortensen, Favre said the Packers' lack of interest in Moss was not the driving reason why he retired.
"This is not about the Packers and who they got or who they didn't get. I get along fine with [Thompson] and I get along great with [McCarthy]. Do I agree with them all the time? No. But the bottom line is, none of that stuff affected my decision," Favre said.
McCarthy said he and Favre had never discussed bringing in Moss.
"But I can tell you one thing, never once in all my conversations with Brett this offseason has he ever asked or told me that we had to have Randy Moss for him to come back and play," McCarthy told Mortensen. "Randy Moss' name never came up once. And it bothers me that [Favre's agent] has made this an issue." Surrounded by an underrated group of wide receivers who proved hard to tackle after the catch, Favre had a career-high completion percentage of 66.5 in 2007. He threw for 4,155 yards, 28 touchdowns and only 15 interceptions.
It was a remarkable turnaround from the past two seasons. In 2005, Favre's final season under former head coach Mike Sherman, he threw a career-worst 29 interceptions as the Packers went 4-12. In 2006 he completed 56 percent of his passes and threw for as many touchdowns (18) as interceptions.
Given Favre's career resurgence, it was widely assumed that he was leaning toward returning for the 2008 season.
He even said as much just before the Packers' Jan. 12 divisional playoff game against Seattle, telling his hometown newspaper that he wasn't approaching the game as if it would be his last and was more optimistic than in years past about returning.
"For the first time in three years, I haven't thought this could be my last game," Favre told the Biloxi [Miss.] Sun Herald. "I would like to continue longer."
The Falcons selected Favre out of Southern Miss with the 33rd pick of the 1991 NFL draft. He was then traded to Green Bay for the 17th overall pick in the 1992 draft and appeared in his first Packers game on Sept. 20 of that year, replacing injured starter Don Majkowski and leading Green Bay to a 24-23 come-from-behind victory over the Cincinnati Bengals. He was named the starter later in the season, a role he never relinquished.
By nature of his style of play -- he was willing to roll the dice on long throws and able to force passes into tight coverage thanks to a strong right arm -- Favre had a flair for the dramatic on the field. But his off-the-field life has been full of drama as well.
He nearly died in a car accident in Mississippi in 1990, before his senior season at Southern Mississippi. In May 1996, Favre acknowledged he had developed an addiction to the painkiller Vicodin and sought treatment. In 2004, his wife Deanna announced she was fighting breast cancer, for which she was successfully treated. That same year, his brother in law was killed in an ATV accident. And in 2005, Hurricane Katrina destroyed his boyhood home in Kiln, Miss., and damaged his current home in Hattiesburg.
Favre's off-field and on-field lives collided Dec. 21, 2003, when his father suffered a fatal heart attack in his home town of Kiln, Miss. The next night, Favre chose to play the Packers' scheduled "Monday Night Football" game against the Raiders and threw for 399 yards and four touchdowns in a 41-7 win.