Marcus Dixon, 19, was released on his own recognizance after 15 months behind bars. Dixon was joyfully reunited with his legal guardians, Ken and Peri Jones.
"It's a feeling that I just can't describe," Ken Jones told CBS News' Early Show. "I'm just so glad that he got to come home."
The court ruled 4-3 that Dixon, who was 18 at the time, should have been prosecuted solely on a lesser charge of misdemeanor statutory rape rather than aggravated child molestation.
Dixon had claimed he was targeted by prosecutors because he is black and the girl, who was 15 at the time, is white. His case drew protests from the NAACP.
Dixon was acquitted of rape but found guilty of aggravated child molestation, which carries a mandatory 10-year sentence, and statutory rape. The high court let stand the statutory rape conviction, punishable by up to a year behind bars — more time than Dixon served.
Ken Jones said he called Dixon after hearing about the decision. "Marcus was crying, I was crying," he said. "We were both doing the dance."
Prosecutor Leigh Patterson said she would ask the Supreme Court to reconsider its ruling.
Dixon was an honor student and star athlete at Pepperell High School in Rome, and his scholarship to Vanderbilt University in Nashville, Tenn., was revoked after his arrest.
Dixon is scheduled to stand trial this month on a separate sexual battery charge for allegedly putting his hands in the shorts of a 14-year-old student.
He had sex with the younger student at a trailer after school in February 2003. The defense said the sex was consensual; prosecutors argued Dixon forced himself on the girl.
The girl testified that she tried to escape from the trailer, where she was working as a custodian, but did not scream or shout for help. "I was too scared. I was afraid he'd hit me or something," she said.
Dixon's case led some lawmakers to push for change in the state's mandatory sentencing law, and members of the state House black caucus broke into applause Monday when the court's ruling was announced.
"What a joy it is in our state to see justice for a young man," said state Rep. Alisha Thomas-Morgan.
Kweisi Mfume, president of the National Association for the Advancement of Colored People, said the ruling is a victory against arbitrary law enforcement.
"We thought the law was being unfairly applied. Mandatory minimums just don't work. This is really more than a black-and-white case," Mfume said.
The girl's attorney, Mike Prieto, said: "It terrifies me the message this sends to all the young women in the state of Georgia when they're confronted with a star athlete who wants to have sex."