Vick wrote the letter before his 23-month prison sentence was handed down Monday. He said his life was ruined by his crimes, the Newport News (Va.) Daily Press reported Friday.
"Honestly, I wish I had never been involved in dogfighting," Vick wrote to U.S. District Judge Henry Hudson. "As a result, I've lost everything -- my good name, job, endorsements, and now my freedom. So, sitting here today I can say I've learned an invaluable lesson."
Vick's letter was released by his defense team Thursday along with letters sent to Hudson from Vick's mother, retired baseball star Hank Aaron, boxing champion George Foreman, former coaches, the mayor of Atlanta and multiple fans.
The letters all urged the judge to use leniency in sentencing the former quarterback but Hudson actually gave Vick a sentence longer than the 12-to-18 month term prosecutors had suggested.
Notable deaths of 2014 [PHOTOS]
Michael Sam cut from the Dallas Cowboys