Long made the announcement Saturday night on social media, sharing a photo of a red cup in his hand and the mountains in the distance.
The Eagles released a statement congratulating Long, saying, in part, "He will always be part of the Eagles family."
"There aren't many players who can say they won back-to-back Super Bowls and the NFL's Walter Payton Man of the Year award," the Eagles said. "There's no question that his work ethic combined with his unique talent made him into one of the greatest of this era's professional athletes. We're very thankful Chris chose to play for the Philadelphia Eagles."
Cheers. Been a hell of a journey. Eleven years and I can honestly say I put my soul into every minute of it. Highs and lows. I've seen them both and I appreciate the perspective. Gratitude and love to those who lifted me up. pic.twitter.com/Ap8zi73Ifl— Chris Long (@JOEL9ONE) May 19, 2019
Long, 34, spent much of the offseason weighing whether to retire or play another season. He made it clear that his role would need to be right if he were to return for a 12th NFL season.
Long wanted ample opportunity to get after the quarterback. With Brandon Graham and Derek Barnett slated to be the Eagles' starters and defensive tackle Malik Jackson likely to stay on the field on third down, Long's playing time in pass-rushing situations would have been more limited than he'd like.
"It's kind of like at the amusement park, when they click that seat belt on, the roller coaster going -- you can't get out. There's no quitting," Long told ESPN earlier this offseason. "Some guys might think differently, but when you're in, you're in, so I want to make sure I'm in. I think most players need to do that, and I'm just honest about it. Maybe some guys just aren't telling the truth. But it's all about the situation for me. I know I can still play. I think I played well, especially in the second half of the year this year, once I got healthy and I got more snaps, so we'll see."
Long was a part of two Super Bowl championship teams in back-to-back seasons -- with the New England Patriots in 2016 and then the Eagles in 2017, helping deliver Philadelphia its first Lombardi Trophy.
Selected second overall by St. Louis in the 2008 NFL draft, he spent the first eight seasons of his career with the Rams before being released in 2016 as injuries limited his production. His 6.5 sacks this past season were his most since 2013.
The son of NFL legend Howie Long, he posted 70 career sacks and 85 tackles for loss over his career.
For all of his on-field success, Long's legacy largely will be defined by the way he used his platform to maximize his humanitarian efforts. Through his organization, Waterboys, he has helped provide more than 200,000 people with clean water in Africa, building close to 60 water wells in Tanzania.
Long donated his entire 2017 salary to educational efforts in Virginia and a quarter of his 2018 salary to help get books into the hands of kids in underserved neighborhoods.
This offseason, he was named the Walter Payton NFL Man of the Year, an award that recognizes a player for excellence on and off the field.
"I think everybody knows that they're not as good of a person as [portrayed]; I think if you're honest with yourself, everybody has a lot of work to do," he said. "It's always en vogue to say, 'Man, I'm humbled,' but I mean it. There are things that I'm constantly working on.
"Listen, are we the most productive foundation off the field in an NFL locker room? I believe that. I believe our productivity as a foundation and my productivity off the field is really solid. I just think if the award is meant to be given to a clean-cut guy who never screws up or doesn't have much to work on -- I'm a work in progress and anybody who knows me would tell you that. I try to do the right thing and sometimes you're going to fall short. I was happy to accept the award on behalf of everybody who has been a part of it. I just think it's a hell of an honor, it's a hell of an award for one person to accept and I don't think it's realistic, but I'm happy to accept it."