As he leaves his role, Banner hopes he can re-create that transformation elsewhere in the NFL.
"I love football. I feel like I've learned so much, feel like I've contributed so much, feel like I have a lot to offer," Banner said in an interview in his office. "My hope is to be part of a group that's going to buy a team and be in a position to operate it."
Banner hopes to gather potential owners willing to put up money to buy a team and entrust him to run it. He said he does not have a specific team or area in mind, but is more focused on situation. He'd like to take over a struggling franchise confronting issues similar to those he faced when Jeffrey Lurie bought the Eagles in 1994.
"That way, I think I get kind of a new, fresh challenge," he said. "My personality, my strengths fit better for a turnaround situation. It's very likely that what I do next will involve something that probably isn't going in the right direction . . . and to try to get it fixed."
Banner said he already has heard from some people interested in discussing the idea, but the process probably will take months. For now, he is focusing on the NFL, saying he is "not really" interested in branching out to other sports.
Banner and Lurie, his longtime friend and business associate of 20 years, insisted that Banner had not been pushed out of his job and had planned to make this move since the spring of 2011. If he was going to take on a new venture, it had to begin now, Banner said.
"There's a point at which taking on a big challenge and knowing you'll have the energy you need to for long enough to do it, the window starts to pass," said Banner, who recently turned 59.
Banner also said that in recent years he has spent most of his time managing others, rather than being actively involved in operations.
"Those of you who know me would not particularly describe me as a passive person," he said at a news conference.
Banner, describing a mix of sadness to leave the Eagles and excitement about embarking on a new endeavor, said his priority is identifying the investors he can partner with.
Acquiring a team, however, may prove difficult. NFL teams sell far less often than those in other sports - sales happen less than once every two years, said Marc Ganis, president of SportsCorp Ltd., a sports consulting firm.
Teams that change hands tend to be those controlled by older owners who don't have obvious or willing heirs.
Banner would bring respected business acumen to a new venture. Since Lurie bought the team in 1994 for $185 million, the Eagles' value has grown to $1.2 billion, according to Forbes' latest valuations. (They are the seventh-most valuable NFL franchise, according to Forbes.) Veterans Stadium was replaced by the $512 million Lincoln Financial Field and the $37 million NovaCare Complex, where Banner will keep an office while he works on his new venture.
"He is seen as one of the most competent senior executives in the National Football League," Ganis said, noting that Banner has been through "every major aspect of NFL team ownership," including buying a franchise, developing a new stadium, putting together football and business staffs, and marketing.
"The Eagles have done very well on both ends, both the business end and the football end, and that expertise is rare," said agent Jerrold Colton, who represents former Eagles kicker David Akers.
Banner would want to be the face of a new ownership group, but in Philadelphia he has been a lightning rod. Many saw him as haughty and out of touch, and his unyielding negotiating style led to resentment among some Eagles and, in turn, fans.
Banner acknowledged that he sometimes pushed too hard in negotiations and that some of his tactics made it seem he didn't value cherished players, citing the departure of safety Brian Dawkins as an example. But he said that he aimed to be tough but fair in negotiations and that perceptions of him were exaggerated, pointing out that many free agents chose to join the team and other players re-signed with the Eagles.
Banner absorbed much of the blame for the Eagles' failure to win a championship, despite their years of being close.
"There is no doubt that there's a huge hole in this experience, as amazing as it's been, having not won a Super Bowl," Banner said.
That's part of why it seems odd for him to step away before having achieved that goal.
If the Eagles win it all this year, Banner said in his office, "I may feel like I should have waited a couple of months," he said with a laugh.
He added, though: "I care deeply about all the people here; I want them to succeed."
Contact Jonathan Tamari at 215-854-5214 or firstname.lastname@example.org, or follow on on Twitter @JonathanTamari.