Ryan, 78, left the federal prison in Terre Haute, Ind., five months before his prison term officially ended, having qualified for early release to a halfway house.
Ryan did not stop to talk to reporters before entering the Salvation Army Freedom Center on the city's West Side before dawn. He was accompanied on the ride from the prison by his attorney, another former governor, Jim Thompson, who said Ryan talked during the journey about how good it felt to be out.
"Today is another step in a long journey for George Ryan," Thompson told the mass of reporters gathered outside the facility.
"He's in decent spirits. It is such a stark change from penitentiary life he has to become accustomed again to being on the outside," he said.
Ryan's release means Illinois no longer has the dubious distinction of having two former governors behind bars simultaneously. Ryan's successor, Rod Blagojevich, is now Illinois' lone imprisoned governor. The Democrat is serving a 14-year term for corruption at a federal prison in Colorado.
A jury convicted Ryan in 2006 of racketeering, conspiracy, tax fraud and making false statements to the FBI. Jurors found that Ryan had steered state business to insiders as secretary of state and then as governor for vacations and gifts. He also was accused of stopping an investigation into secretary of state employees accepting bribes for truck driver's licenses.
Ryan, a Republican, drew national attention as governor when he deemed Illinois' capital punishment laws flawed and emptied death row in 2003. That reignited a nationwide debate and led the state to abolish its death penalty in 2011.
While Ryan was in prison, his wife of 55 years died in 2011. Officials allowed Ryan to leave prison to visit her when she was sick with cancer, but he wasn't allowed to attend her funeral. Ryan has suffered from his own health problems, including kidney disease.
For decades, the Salvation Army has run a community program where inmates live for a short time, take classes to learn basic skills and receive counseling, among other things.
Ryan doesn't yet have a job lined up as required by his release. Thompson said they will worry about that once he is through processing at the halfway house.
Former Ryan aide Scott Fawell, also convicted in the corruption investigation, spent time at the West Loop halfway house, which is just a couple of blocks from the United Center, where the Chicago Bulls play. Last week, he described it as being "like a really bad dorm room." But he said "life is a little better" there than in prison.
Inmates at a halfway house get to wear their own clothes, work a job and can be eligible to be in their own homes within weeks, though they still have to keep close contact with prison officials.
Ryan owns a home in Kankakee, about 60 miles south of Chicago.
(Copyright 2013 by The Associated Press. All Rights Reserved.)