Green was released on orders of a judge who considered the recanted testimony of the only witness in the case, the Los Angeles Times reported Friday.
"It's like I'm in a dream," Green, 56, said after his release Thursday from San Quentin State Prison.
"I was wrongly accused. I'm out now, I'm not bitter. I'm happy today."
Green was convicted in the shooting death of a woman at a crack house in South Los Angeles. The only witness, WIllie Finley, said Green was at the scene of the killing, the Times said.
Green went to prison in 1983.
In 2004 Finley reportedly admitted to attorneys that he was under the influence of crack at the time of the shooting and had not seen the gunman clearly.
In light of Finley's revised account of the incident, Los Angeles County Superior Court Judge Stephen A. Marcus reversed Green's conviction.