The Jets, once the team of one of football’s most charismatic quarterbacks, now have another one. They acquired Brett Favre from the Green Bay Packers in a deal late Wednesday night that the Jets hope will ignite excitement for a team that struggles to remain in the headlines in the same city with the Giants and struggles for competitiveness in the same division as the New England Patriots.

“We just felt this was an opportunity to go get somebody of Brett’s stature and what he’s accomplished,” said Jets General Manager Mike Tannenbaum.

The terms of the trade were not announced, although it was believed to be for a fourth-round pick that, depending on Favre’s performance and the team’s results, could increase in value, all the way up to a first-round selection. The trade was first reported Wednesday night by FoxSports.com.

Quarterback Chad Pennington, a former first round draft pick, is loved and respected in the Jets’ locker room, but Tannenbaum said early Thursday morning that the Jets will part ways with him now that Favre is on board.

“It’s a bittersweet moment for us,” Tannenbaum said. “I have all the respect in the world for Chad as a person and as a player. He gave his heart and soul to this organization for a long, long time.”

Tannenbaum said that Favre had to be convinced to consider the Jets and that Favre talked directly to the Jets only in the last two days. Favre and his family favored the Tampa Bay Buccaneers, where Favre knew Coach Jon Gruden and his offense, all the way up to the moment when the Jets made the deal. The extent of Favre’s commitment to the Jets remains a question.

“We’re going to take things one year at a time,” Tannenbaum said. “We’re excited to have Brett on the team for this year. This was a situation we were monitoring, and when we felt there was an opportunity, we felt it was the right thing to do to go after Brett.”

“Obviously there were some concerns,” Tannenbaum said. “He’s coming to a new city, he’s been in one system for 16 years, there’s not a lot of connection with Brett and our coaching staff. We were able to talk through moving to the northeast. We felt really good about it, and we’re excited that he’s with us.”

For Favre, the trade ends a protracted divorce from the Packers that captivated the N.F.L. and set Favre free from the team that he led to a Super Bowl title and for whom he had become an icon. Favre also won three Most Valuable Player awards in Green Bay, but when the Packers did not welcome him back after he reversed course on his retirement, Favre became the unexpected object of the Jets’ ardor. For weeks, the Jets were on the periphery of trade talks as Favre’s drama droned on. But Favre changes the image of a team that is often overlooked, bringing with him a glamour that has been absent from the franchise at least since Bill Parcells left after the 2000 season and star power that has not been present since Joe Namath took his fur coats and bad knees and went to Los Angeles in 1977 to finish his career. The Jets’ meeting against the Patriots in Week 2 instantly becomes more interesting.

“Brett has had a long and storied career in Green Bay, and the Packers owe him a tremendous debt of gratitude for everything he accomplished on the field and for the impact he made in the state,” Ted Thompson, the Packers’ general manager, and Mark Murphy, the team’s president, said in a joint statement. “It is with some sadness that we make this announcement, but also with the desire for certainty that will allow us to move the team and organization forward in the most positive way possible.”

The Jets underwent a $100 million makeover during the off-season, augmenting their offensive line and remaking their defense. But they had been conducting a quarterback competition in training camp between Pennington and Kellen Clemens, two options that last season produced just four victories.

But the appeal of Favre is obvious: he had a turn-back-the-clock season last year, completing 66 percent of his passes and leading the Packers to the National Football Conference Championship game. With his arrival he likely makes the Jets a viable American Football Conference wild-card team. Even at 38, he is remarkably durable, having started 253 consecutive games, and he holds almost every major N.F.L. career passing record. And his marketing potential in New York is enormous, which was surely part of the Jets’ pitch to Favre.

He will be a huge draw for the Jets, who will move to their new training complex in New Jersey at the end of training camp, and he gives the franchise a famous face as they begin a campaign centered around the 2010 opening of the stadium they will share with the Giants. Favre has no previous relationship with Coach Eric Mangini and the offensive coordinator Brian Schottenheimer, and he will be forced to learn an unfamiliar offense on the fly. Favre’s style has always had a seat-of-his-pants element, and that has led to a striking propensity to throw interceptions. That problem could hamper him with the Jets, particularly early in the season as he tries to find his comfort zone with new receivers. But as he left Green Bay Wednesday morning, Favre expressed weariness at his predicament — the falling out with the Packers had taken a toll on him and his family — and a desire to merely join a team.

“It’s in everyone’s best interest to do it quicker than later,” Favre told The Hattiesburg American. “I won’t say we’re running out of time, but I need to get into a camp somewhere.”

And now, surprisingly, he will be in camp for the Jets, a quick flirtation turning into a franchise-changing decision in just 24 hours.

“My gut feeling for a long time was I just didn’t think this would come to fruition,” Tannenbaum said. “We had a cursory monitoring situation going on for a number of days. We put an oar in the water and things heated up at the end.”