The 61-year-old coach will earn about $5.25 million annually, a $2 million increase over last season and what he was to have earned this year. Seattle's Mike Holmgren is the NFL's top-paid coach at $8 million a year.
"For Tom Coughlin, 'coach' is not just a title, it's a responsibility," said Steve Tisch, the team's chairman and executive vice president. "He took a group of football players and molded them into the best team in the world. We are honored he will lead the New York Giants for many more years and know that the team and its fans are better for his amazing contributions."
Coughlin had been on the verge of being fired after the Giants went 8-8 in 2006 and were eliminated in the first round of the playoffs for the second straight year.
The Giants (14-6) and Coughlin both staged remarkable turnarounds, capped by a 17-14 win over previously unbeaten New England in the Super Bowl in Glendale, Ariz.
Coughlin said that becoming the Giants' coach in 2004 was "the fulfillment of a dream of a lifetime."
"And now to be able to continue in that capacity with this organization, with this leadership, with this football team and with my coaching staff in place is something my family and I are extremely excited about," Coughlin said.
Coughlin was an assistant coach on Bill Parcells' staff when the Giants won the Super Bowl in 1991. He left to coach Boston College and eventually took the head job with the expansion Jacksonville Jaguars. Coughlin has a 103-89 record in 12 NFL seasons, including a 35-29 mark in four seasons with New York.
Gary O'Hagan, Coughlin's agent, said Saturday the deal included a "great" incentive package but would not elaborate. He said this may not be Coughlin's last contract.
"I think Tom is in great shape physically and takes great care of himself," O'Hagan said. "I don't think (65) is a magic number for him. In the corporate world it's a magic number for retirement. I don't think he sees it as the end of the line."
Veteran punter Jeff Feagles said Coughlin is deserving.
"We know what we'll be getting with Tom, and that makes a difference to a player," said Feagles, who signed a two-year contract Feb. 12. "You bring somebody else in, you never know if they're going to change your routine. But we all know how structured Tom is. And now we all know he'll be around for a few more years."
Once an unyielding disciplinarian, Coughlin became a kinder, gentler coach. He still demanded perfection, but he was wise enough to enlist a core of veterans to get his message across.
Coughlin went to his leadership council, and told them there was no other group that he would rather be coaching.
New York clinched a playoff berth by rallying to beat Buffalo in the next-to-last week. The last week of the regular season and the playoffs were magical.
The performance gave the Giants confidence entering the playoffs. They beat Tampa Bay in the wild-card game, avenged two earlier losses to the NFC East champion Cowboys in the conference semifinal and then got back at Brett Favre and the Packers in overtime on a frigid day in Green Bay, earning their fourth Super Bowl trip.
"I am looking forward to working with Tom for the next four years and beyond," general manager Jerry Reese said. "Our players feed off his energy, and his dedication to winning is unprecedented."
Copyright 2008 by The Associated Press