Former media mogul Conrad Black quietly left a federal prison in Florida on Wednesday, free on bond after serving just two years of a 6 1/2—year sentence for defrauding investors, officials said.

Earlier in the day, U.S. District Judge Amy St. Eve in Chicago set his bond at $2 million and ordered him not to leave the country, pending the outcome of the appeal of his 2007 conviction. She set a Friday court hearing for the former Hollinger International Inc. chairman to hear the conditions of his release and also was considering a request from Black’s attorneys to let him return to Canada, where he owns a home in Toronto.

Attorney Miguel Estrada said he expected Black to return to his Palm Beach home, but not for long.

“Palm Beach is not an option long term,” Mr. Estrada said after the Chicago hearing. “His home is in Canada.”

Black left a low security facility at the Coleman Federal Correctional Complex seemingly undetected by the dozens of reporters waiting in the nearly 100 degree F (37 C) weather outside the rural prison.

Prison spokesman Gary Miller in Coleman, Florida, confirmed Black’s release but declined to offer details.

The bond was paid by Black’s friend and former business partner, Roger Hertog.

Mr. Estrada said the Federal Bureau of Prisons issued Black an ID that would allow him to fly to Chicago.

In 2007, Black and three former Hollinger executives were convicted of defrauding shareholders out of $6.1 million. One of the prosecutors’ arguments was that Black deprived the company of his faithful services as a corporate officer, breaking the so—called “honest services” law.

Black also was convicted of obstruction of justice after jurors saw a video of him carrying boxes of documents out of his offices, loading them into his car and driving off with them. The documents were sought by government investigators.

The U.S. Supreme Court last month limited the scope of the honest services law, leaving it to the 7th Circuit to determine whether to overturn Black’s conviction in whole or in part. The appeals court on Monday granted Black’s motion for bail as he appeals his fraud conviction.

It remains unclear, however, where Black’s case stands in light of the Supreme Court’s ruling. Before their weeks-long deliberation in 2007, jurors were instructed they could convict Black either on the conventional or “honest—services” types of fraud. But it’s unclear which charge the jury relied on.

Federal prosecutors have said they would continue to urge any honest services convictions for Black be upheld. U.S. Attorney’s office spokesman Randall Samborn in Chicago declined to discuss the case Wednesday pending the appeal.

Hollinger International once owned the Chicago Sun—Times, The Daily Telegraph of London, The Jerusalem Post and hundreds of community papers in the U.S. and Canada.

At the core of the charges against Black was his strategy, starting in 1998, of selling off the bulk of the small community papers, which were published in smaller cities across the United States and Canada.

Black and other Hollinger executives received millions of dollars in payments from the companies that bought the community papers in return for promises they would not return to compete with the new owners.

Prosecutors said the executives pocketed the money, which they said belonged to shareholders, without telling Hollinger’s board of directors.

But Black’s lawyers have maintained that federal prosecutors failed to muster adequate evidence that he defrauded anyone or tried to hide key documents.