"I know I've done some terrible things, made a horrible mistake. Now I want to be part of the solution and not the problem," Vick said Friday, referring to his conviction for his role in running a dogfighting ring.
Vick was introduced by the Eagles a day after signing a one-year deal for $1.6 million with a team option for a second year for $5.2 million. None of the money is guaranteed, so the Eagles face no financial risk if Vick does not make the team.
Vick, dressed in a gray pinstriped suit, was flanked by Eagles coach Andy Reid and mentor Tony Dungy.
"I really got the sense he wanted to do some great things," Dungy said. "He wanted to be a positive role model for young people. He wanted to get back to his family."
The 29-year-old Vick has been out of action since 2006. The former Atlanta Falcons star served 18 months of a 23-month sentence in federal prison, with the rest of it in home confinement.
Vick also was suspended indefinitely by the NFL.
"For the life of me, I can't understand why I was involved in such pointless activity," Vick said. "Why did I risk so much at the pinnacle of my career?"
The turnout at the Eagles practice facility Friday was the largest in years, with more than 100 media members and nearly two dozen cameras there to hear Vick.
Vick spoke softly during the 26-minute news conference, saying he felt remorse even as he was involved in dogfighting.
"There was a point in my life where I felt it was wrong and I knew it was wrong," he said. "To this day I have to live with that shame and that embarrassment."
Vick, who said he wants to be the "best ambassador to the NFL and community," said he hoped to play in a regular-season game soon. He asked for a second chance, but expected he won't be easily pardoned by fans or the general public.
"Michael has been given a good opportunity to restart his career in the NFL, and we wish him well," the Falcons said in a statement.
Vick knows he might never be welcomed back by some people.
"I understand to a certain degree, but our country is a country of second chances," he said. "I paid my debt to society. I spent two years in prison. ... That was a humbling experience. I can't explain how deeply hurt and how sorry I was."
The signing drew fire from a local animal rescue group.
Bill Smith, founder of Main Line Animal Rescue in the Philadelphia suburbs, said the group will be renting three billboards near the Eagles' stadium blasting the signing of Vick.
Smith said he was stunned while listening to Vick at the news conference.
"I'm really shocked that he's coming to Philadelphia," Smith said. "He kept talking about second chances. His dogs didn't have a second chance ... There are a lot of people out there who deserve second chances more than Michael Vick."
The Philadelphia Daily News blasted the decision in headlines for Friday's edition, with a front-page headline blaring "Hide Your Dogs" and "What Are They Thinking?" on the back.
A national group said it would be watching to see whether Vick lives up to his pledge.
Ed Sayres, president of the American Society for the Prevention of Cruelty to Animals, said in a statement that the group "expects Mr. Vick to express remorse for his actions, as well as display more compassion and sound judgment this time around than he did during his previous tenure with the NFL. We hope that Mr. Vick uses his stature for the betterment of the community and the advancement of the issue of animal cruelty."
Eagles owner Jeffrey Lurie said he did serious "soul-searching" regarding Vick. The owner said he met with Vick for hours and is convinced he can become a force in stopping animal cruelty.
"I needed to see a lot of self-hatred in order to approve this," Lurie said.
But Lurie said if Vick is not proactive in working with the community and the Humane Society, then his signing will be a "terrible decision."
"There's no third chances and we know that. If it isn't fulfilled the way we expect it to be, then it will be the end," Lurie said.
Commissioner Roger Goodell conditionally lifted Vick's suspension on July 27, allowing him to sign with a team, practice and play in the last two preseason games. Vick can travel with the Eagles for their preseason game in Indianapolis on Thursday, but he cannot play until Philadelphia hosts Jacksonville on Aug. 27.
Once the season begins, Vick can participate in all team activities except games, and Goodell said he would consider Vick for full reinstatement by Week 6 (Oct. 18-19) at the latest.
"I have said several times in recent weeks that I want Michael to be one of the NFL's success stories as an individual and as a football player," Goodell said. "I believe he can accomplish both goals with the Eagles organization, which has done an outstanding job in the community and on the field these last 15 years under the direction of owner Jeffrey Lurie. I know the Eagles will provide strong support but, ultimately, Michael's success is up to him and the decisions he makes."
The Eagles reached the NFC Championship Game last season, but are looking for their elusive first Super Bowl victory.
Vick thanked Reid and the Eagles' ownership for taking a gamble on him. He also personally thanked Eagles starter Donovan McNabb for lobbying the team on his behalf.
"I'm glad that Coach Reid and the rest of the organization stepped forward," Vick said. "I'm glad I got the opportunity and the second chance. I won't disappoint."
Asked if some Eagles fans will be angry that the team signed Vick, Reid said: "Not everybody agrees with every decision. I expect the public to have some questions initially."
Reid said he hopes fans will trust that the team did its homework on Vick and signed him because the team believes the quarterback is a changed man who is ready to return to football.
Frank Beamer, Vick's college coach at Virginia Tech, said in a statement: "I believe Michael Vick understands very clearly the wrong that he did, and is very intent on making things right. I think that this is an opportunity for him to help a lot of people to not go down the same path that he went down. I look forward to watching the Eagles this season."
Vick, who said he has no more pets, said he planned to prove he can help more animals than he has hurt.
Vick will practice with the Eagles for the first time Saturday.
"I'm ready to go," he said.
The Eagles reportedly were not the first team to extend an offer to Vick. FoxSports.com reported that the Cincinnati Bengals first offered Vick a two-year deal worth about $2.3 million.
Reid called Vick "one of the greatest quarterbacks" in the league two years ago. With McNabb firmly entrenched as the starter, Vick will have to look at playing another position.
The most likely scenario would be for the Eagles to use Vick in a variation of the Wildcat offense that the Miami Dolphins made popular last season. Vick also is familiar with the West Coast offense, though he ran a different version with Atlanta than the one Philadelphia uses.
Reid did not specifically address how he would use Vick.
"I will say, though, that he will contribute," Reid said. "You can ask defensive coordinators on other teams if they're worried about that."
The 29-year-old Vick said he is content playing any role on offense.
"Whatever Coach Reid decides on, that's what I will do," Vick said. "I'm just here to contribute and help win a Super Bowl."
The signing also will enable Vick to take care of his debt. The most recent bankruptcy court plan allowed him to keep the first $750,000 of his salary, and he then will be expected to pay creditors with a percentage that increases as his salary goes up. Vick must also pay his bankruptcy lawyers, who are claiming at least $3.5 million in fees.
Vick can earn an additional $3 million in incentives in the two years of the contract, sources told ESPN.com's Len Pasquarelli. None of the money is guaranteed, so the Eagles face no financial risk if Vick does not make the team.
Information from The Associated Press and ESPN.com's Lester Munson was used in this report.