Kevin Dugar walked out of the Cook County Jail around 9:30 p.m.
He's free now because his twin brother, Karl Smith, claims he actually pulled the trigger in a 2003 shooting on the North Side that killed a rival gang member and injured another at Sheridan Road and Argyle Street in Uptown.
Smith is already serving a 99-year sentence for a violent home invasion in which a child was shot in the head.
In 2018, a judge said Smith's confession was not credible, saying he'd been denied an appeal and stood no chance of being released. The judge also denied Dugar a new trial.
But the Northwest Center of Wrongful Convictions appealed Dugar's case. Another judge reviewed it, and, Tuesday morning, said Dugar should be released.
Dugar's attorney said he hopes a new trial will never come, and instead the Cook County State's Attorney's Office will review the evidence and agree to throw it out.
"He is a free man tonight, and it's long overdue after 20 long years," attorney Ron Safer said.
Dugar was met by family members at Cook County Jail.