Vick left Leavenworth medium security prison in Kansas early Wednesday, according to spokeswoman Traci Billingsley.
He was to travel to his home in Hampton, Virginia, where he would begin a period of supervised home confinement, according to media reports.
The former Atlanta Falcons quarterback pleaded guilty in 2007 and was convicted of conspiracy charges in an interstate dogfighting enterprise on another of his properties in rural Virginia.
The case made national headlines and generated debate about dogfighting and the animal cruelty associated with it. Vick was also vilified as a fallen sporting hero.
Vick was the No. 1 pick in the 2001 NFL draft and a three-time All-Pro quarterback with the Falcons. His lawyers say he would like to play professionally again.