The Devils will receive a conditional third-round 2011 draft pick in return.
Langenbrunner, 35, is earning $2.8 million this season. He's an unrestricted free agent July 1, and with the season at about the midway point, the Stars will be responsible for about $1.4 million of his salary.
Langenbrunner was scratched from Thursday night's game against Philadelphia as the Devils finalized the deal. He has a no-trade clause and had to OK the move.
"I am excited to come to back," said Langenbrunner, who was drafted by the Stars. "Dallas gave me my start in the NHL and I have a lot of great memories of playing for that organization and in that city. I am excited about where that team is headed and excited to come be a part of it."
Langenbrunner was expected to be in North Texas by Friday night, but the Stars said he wouldn't play against the New York Rangers.
Devils general manager Lou Lamoriello said on a conference call that the transaction took place late Thursday but was delayed because of the Dallas ownership situation and the need for league approval. The league has been helping to run the Stars while Tom Hicks looks for a buyer.
"Lenders and the league realize our situation," Stars general manager Joe Nieuwendyk said. "They know the situation we're facing. They've given us the go-ahead to do what we think is right for the hockey club. "
The Devils, who have a disappointing 22 points this season and are languishing in last place in the Atlantic Division, are making moves nobody expected at the start of the season but what Lamoriello believes the club needs now.
"When it's a quality person like Jamie has been, it's difficult," Lamoriello said. "Unfortunately in the position we're in ... decisions have to be made.
"Right now we have to all become part of the solution and not be part of the problem."
Lamoriello didn't want to use the word "rebuild," but he said future moves could be on the horizon.
"There could be more, yes." he said.
Lamoriello was adamant that he will not look to shop Martin Brodeur, and that the team will try to re-sign injured left winger Zach Parise, who is set to become a restricted free agent at season's end.
"We certainly want Zach back. We'll do everything we can to re-sign him," Lamoriello said.
Langenbrunner has four goals and 10 assists this season, his eighth full season with the Devils.
"We had high expectations coming into this season, like we do every year, and obviously we have not lived up to that," Langenbrunner said. "It's been a very difficult few months for all of us. It's been home seven, eight years now for me. The organization has been great to me and given me lots of opportunities. I won a Stanley Cup with these guys here and I have a lot of great friends here, so it's going to be hard leaving that."
"I know Jamie probably better than anybody," Nieuwendyk said. "I think there's a number of fronts where he fits in well with our group. We haven't had a right shots for quite some time. We've been missing a right shot, power-play presence. From a performance standpoint he's really going to help us."
"I am going to do what I can to play the game I know how to play. If that's stepping in on the third line, fourth line, second line or whatever they need me to do. I have no issues," Langenbrunner said. "Obviously it's a team that's worked hard to put themselves in a good position and I just want to come in and support that."
Nieuwendyk likes what Langenbrunner brings off the ice.
"I know the character of Jamie and I know he's going to be a terrific fit for us in the locker room," Nieuwendyk said. "He's familiar with our organization, familiar with a couple of our players. It helps for where we are currently to have a guy that is the type of leader he is."
The Stars lead the Pacific Division this season with 52 points but could use some offensive punch. Langenbrunner's best season came in 2008-09, when he had 29 goals and 40 assists.
"We're halfway through the season and I think all of us are really happy where we're at," Nieuwendyk said. "There is a good feeling in the locker room, a belief in the locker room. I think this move will strengthen that belief."
Langenbrunner has won Stanley Cups with the Stars in 1998-99 and the Devils in 2002-03.
"All of our fans got to see first-hand what kind of a player Jamie is when he broke into the league in the '90s and was part of our Stanley Cup team in 1999," Nieuwendyk said. "We are thrilled to be able to bring him back to Dallas."
Dallas last week signed defenseman Trevor Daley to a $19.8 million, six-year contract extension through 2017. Stars top scorer Brad Richards can become a free agent after the season and Nieuwendyk reiterated Friday his desire to re-sign the center.
Lamoriello explained the conditional draft pick:
If the Stars win their first-round playoff series, the pick becomes a second-rounder.
If the Stars re-sign Langenbrunner before July 1, the pick becomes a second-rounder.
If the Stars sign Langenbrunner after July 1, then the Devils give the Stars a third-round pick and get a second-round pick in return.
Lamoriello indicated there would be no immediate replacement for Langenbrunner as captain.
He also noted that because the team was not going to re-sign Langenbrunner, he wanted to give more ice time to younger players such as rookie center Mattias Tedenby.
Information from ESPN.com's Pierre LeBrun, ESPNNewYork.com's Mike Mazzeo, ESPNDallas.com's Mark Stepneski and The Associated Press was used in this report.