The 83-year-old Cosby walked out of the State Correctional Institution Phoenix in Montgomery County, Pennsylvania, Wednesday afternoon, officials told ABC News.
Cosby's publicist, Andrew Wyatt, told ABC News earlier Wednesday that he was going to pick Cosby up at the prison. Cosby has served a little less than two years of his sentence.
Cosby was sentenced in September 2018 to three to 10 years in state prison for allegedly drugging and sexually assaulting former Temple University employee Andrea Constand in 2004.
Last year, the Pennsylvania Supreme Court agreed to hear two points in Cosby's appeal to overturn his 2018 sexual assault conviction.
One was the admission into trial of "prior bad acts" witnesses and Cosby's 2005-2006 quaalude deposition. The appeal argued that the trial judge erred in allowing Cosby's prior deposition about using quaaludes during consensual sexual encounters with women in the 1970s at trial.
The second point was a written agreement from previous Montgomery County prosecutor Bruce Castor not to criminally prosecute Cosby in the Constand case.
Castor had testified that while he was district attorney, he promised Cosby he would not file criminal charges if the entertainer would testify in a civil lawsuit Constand filed against Cosby in 2005.
Cosby testified during four days of depositions by Constand's attorneys, and the civil lawsuit was settled for more than $3 million in 2006.
Prosecutor Kevin R. Steele later brought criminal charges against Cosby in 2015 after succeeding Castor as the county's district attorney.
Two lower courts, including a three-judge panel of Pennsylvania Superior Court jurists, had previously refused to overturn the comedian's conviction.
Despite the deluge of accusations against him, Cosby has maintained he never engaged in non-consensual sex.