McCallum sobbed as D.A. Kenneth Thompson concluded he and co-defendant Willie Stuckey had confessed falsely as teenagers to kidnapping and killing a stranger and taking a joyride in his car.
His cause was championed by Carter who, shortly before his death in Toronto earlier this year, again called for McCallum's release. The former boxer worked for decades to free the wrongfully imprisoned, after spending almost 20 years in prison for a triple murder conviction that was later overturned.
Carter worked on McCallum's bid for exoneration for a decade after getting a letter from him.
"My single regret in life is that David McCallum … is still in prison," Carter wrote in an op-ed in the New York Daily News in February.
McCallum and Stuckey quickly recanted their confessions in the October 1985 killing of Nathan Blenner, but they were found guilty and lost appeals. Thompson's predecessor reviewed the convictions and decided to stand by them last year, but Thompson said the convictions hinged on untrue confessions, made by 16-year-olds, rife with inaccuracies and peppered with details seemingly supplied by police.
Stuckey wasn't in court to be freed. He died in prison in 2001.
"After 29 years, it's a bittersweet moment because I'm walking out alone," McCallum, 45, said as he left court to hugs from relatives and applause from supporters.
But, he said, "freedom feels great."