Michael Strahan won't be defending his first Super Bowl title.

The seven-time Pro Bowl defensive end has decided to retire after a 15-year NFL career with the New York Giants that was capped by a Super Bowl title four months ago.

The 36-year-old Strahan, who was the NFL's active leader in sacks, informed the front office in the morning without telling his coaches and teammates.

"I'm just finding out about it; let me get organized," coach Tom Coughlin said after a team workout.

Strahan and the Giants will have a press conference on Tuesday at 11:30 a.m. ET. It will be broadcast live on NFL Network and NFL.com.

Strahan is walking away from a $4 million salary for the final year of his contract. He has long said he wants a job in television.

Tony Agnone, Strahan's agent, said the Giants offered Strahan more money to play another season, but that was never the key issue. He noted that winning the championship might have been most important for Strahan.

"I really believe that was it," Agnone told The Associated Press. "He really felt he has a chance to repeat this year, so it was tough to walk away."

Giants co-owner John Mara was disappointed after Strahan telephoned him to say he was leaving football.

"I told him he's been a great Giant," Mara said. "He thanked me for everything the organization has done for him. I said, 'I think you've done more for us than we can ever do for you."'

Strahan had said in published reports over the last several weeks that he had made his decision on retirement, but wanted to take extra time before announcing it to make sure that it was the correct decision.

"I knew it was going to (eventually) happen," quarterback Eli Manning said. "He had a tremendous career. If that is the case, he picked a great season to go out on."

Fellow Pro Bowl defensive end Osi Umenyiora was told of the retirement as he walked to the locker room after practice.

"I talked to Mike last week and he told me he was still unsure," Umenyiora said. "He was really, really thinking about it, but I didn't think he was going to do it today."

Strahan was the Giants' leader in the locker room. He taught the young defensive ends how to play the position. He was also a gym rat, spending as much time working out as the youngest free agent trying to win a roster spot.

"It's a very, very sad day for me personally," Umenyiora said. "I loved him like a brother. You put in 15 strong years in the NFL, man that is something in this day and age is impossible to do."

Strahan walks away from the game with Hall of Fame credentials and a Super Bowl ring, leading the Giants to a 17-14 victory over the New England Patriots in Super Bowl XLII in what turned out to be his final game.

Strahan and the Giants went through a similar process last offseason, albeit with a different outcome. Strahan mulled retirement and missed all of training camp before reporting to the Giants on Sept. 4 and playing in the season-opener five days later. Strahan was outstanding in his final season, starting 15 of 16 games and finishing with 57 total tackles and 9.0 sacks.

"I am very happy for him," said receiver Amani Toomer, who played 12 seasons with Strahan. "I think he is going to find a way on his feet. I just wish him the best."

A second-round pick in the 1993 NFL Draft out of Texas Southern University, Strahan is the Giants' career sacks leader with 141.5. Hall of Famer Lawrence Taylor had the old mark of 132.5, although that total does not included 9.5 the linebacker had as a rookie in 1981, the year before sacks became an official statistic.

Strahan set the single-season mark of 22.5 sacks in 2001, getting the last one in the final game of the season when Brett Favre mysteriously fell late in the game, and No. 92 got credit for the sack. He became the second player in NFL history to lead the league in sacks on two occassions, also posting an NFL-best 18.5 in 2003.

Strahan played in 216 career regular-season games, a franchise record, making 205 starts.

Fourth-year pro Justin Tuck is the leading candidate to move into Strahan's starting spot. The Giants also signed veteran defensive end Renaldo Wynn last week.

"The guy has had a great career, 15 years, a first ballot Hall of Famer," Tuck said. "I'm not surprised, just how he did it. I thought he was more of a news conference guy, you know, the whole world watching."

Umenyiora felt Strahan was playing so well he would return this season.

"He retired at the top of his game," he said. "A lot of us don't get the chance to do that."

The Associated Press contributed to this report