"I didn't choose to go the right way, which led to 18 months in prison, which was the toughest time of my life," he said. "Being away from my family, being away from my kids who I adore dearly, and being away from the game of football, doing something so foolish, and I wish I could take it all back.
"I was influenced by so many people when I should have been a leader, not a follower."
The 10-minute talk marked Vick's first anti-dogfighting public appearance in Philadelphia since he signed a one-year, $1.6 million deal with the Eagles on Aug. 13. At the time, he expressed a desire "to be part of the solution and not the problem" by speaking to children around the country about dogfighting.
Speaking without notes, Vick told the hushed assembly Tuesday that his poor decisions imperiled the goals he had set for himself.
"Growing up, I had dreams and I always wanted to have this great, lavish life and make it to the NFL, go and accomplish great things and leave a great legacy. That was my goal from a young kid," Vick said. "My future was promising ... at some point, I got sidetracked. I started listening to my friends and doing some things that were not ethical and not right."
He said he tried to do the right things at school and at home, "but I had another side to me, and it was a dark side."
Vick visited the school with Wayne Pacelle, president and CEO of the Humane Society of the United States. Pacelle has said he met with Vick in prison at the quarterback's request and that Vick sought to work with the group after his release.
Vick and the organization are working on "a national campaign to try to reach especially young people so we can all be voices against organized animal fighting," specifically dogfighting and cockfighting, Pacelle said.
"It's really a test of our character as individuals about being good to those who are less powerful," he said.
Once the highest paid player in the NFL, Vick was suspended from the league following his conviction in August 2007 on charges of conspiracy and organizing the dogfighting ring. He was released from federal custody on July 20.
Several animal rights groups criticized the team's decision to sign the quarterback, saying he is a poor example for young people.
Eagles spokeswoman Pamela Browner-Crawley has said the team has an obligation to the community, and to children particularly, to discourage them from engaging in dogfighting or any animal abuse.
Vick is suspended for the first two games of the regular season and is eligible to play beginning Sept. 27. In two preseason games, Vick completed 11 of 15 passes for 45 yards with one interception and rushed for 36 yards on eight carries with one touchdown.