Danny Fenster, an American journalist, was released from prison in Myanmar on Monday and will be allowed to leave the country, according to a spokeswoman for Bill Richardson, the ex-diplomat who helped secure his freedom.

The release of Mr. Fenster, who was sentenced on Friday to 11 years in prison, is a rare positive development in Myanmar, which has been torn by violence since the military staged a coup in February and began a brutal crackdown against pro-democracy protesters.

“This is the day that you hope will come when you do this work,” said Mr. Richardson, the former U.S. ambassador to the United Nations, who has a long record of winning the release of American prisoners from autocratic countries. “We are so grateful that Danny will finally be able to reconnect with his loved ones, who have been advocating for him all this time, against immense odds.”

Mr. Richardson had met with the junta chief, Senior General Min Aung Hlaing, this month. He returned to the Southeast Asian country in recent days and was flying back to the United States with Mr. Fenster, who had been in prison since May.

After his Nov. 2 meeting with General Min Aung Hlaing, Mr. Richardson said he had not raised the issue of Mr. Fenster’s release but had sought to lay a foundation for future discussions. Madeleine Mahony, Mr. Richardson’s director of media relations, said Mr. Richardson and Mr. Fenster were expected to arrive in the United States on Tuesday.

A court convicted Mr. Fenster on charges of disseminating information that could be harmful to the military, unlawful association with opponents of the regime and violating immigration law. It gave him the maximum possible sentence of 11 years.

Mr. Fenster is the managing editor of Frontier Myanmar magazine. The prosecution based its case on his prior employment with the online news outlet Myanmar Now, which the regime has banned. Mr. Fenster left Myanmar Now in July 2020, more than six months before the coup, but the court found him guilty anyway.

His family said it was “overjoyed” that he was on his way home.

“We cannot wait to hold him in our arms,” the Fenster family said in a statement. “We are tremendously grateful to all the people who have helped secure his release, especially Ambassador Richardson, as well as our friends and the public who have expressed their support and stood by our sides as we endured these long and difficult months.”

Mr. Fenster is one of more than 120 journalists who have been arrested since the coup. About four dozen remain in prison. Another U.S. journalist, Nathan Maung, a co-founder of the online news site Kamayut Media, was arrested in March and released two months later.

Frontier Myanmar, which had backed Mr. Fenster throughout his imprisonment and trial, joined in thanking those who helped free him. “We are relieved that Danny is finally out of prison — somewhere he never should have been in the first place,” said Thomas Kean, the editor in chief.

“We also recognize Danny is one of many journalists in Myanmar who have been unjustly arrested simply for doing their job,” Mr. Kean said. “We call on the military regime to release all of the journalists who remain behind bars in Myanmar.”

Mr. Fenster was arrested on May 24 at Yangon International Airport as he prepared to board a plane and leave the country. The authorities had been searching for “responsible editors” who worked for Myanmar Now, the news outlet reported. Mr. Fenster’s name appeared on that list.

During his nearly six months in detention, Mr. Fenster was held at the 134-year-old Insein Prison, where the military has long sent political prisoners. The colonial-era penitentiary is notorious for its bad conditions, mistreatment and inedible food. Mr. Fenster contracted Covid-19 while in prison and recovered, his family said.

Last week, prosecutors had filed additional charges, of terrorism and sedition, against Mr. Fenster, which are both punishable by up to 20 years in prison. His lawyer said he had no idea what those charges were based on.

Mr. Fenster’s trial was held inside the prison; no relatives or members of the public were allowed to attend. He broke down in tears when the verdict was announced, his lawyer said.

The outdated list of editors provided by the Ministry of Information was the key piece of evidence. His lawyer introduced his record of employment with Frontier Myanmar and his tax return, but the court rejected the defense argument that Mr. Fenster was not guilty because he no longer worked at Myanmar Now.

The charges of disseminating potentially harmful information and unlawful association were based on reports published by Myanmar Now. The immigration charge, added near the end of the court proceedings, was based on the contention that Mr. Fenster had violated the terms of his visa by breaking the other laws.

Since the military seized power in the Feb. 1 coup, it has been merciless in its crackdown on street protests and opposition leaders. At least 1,260 people have been killed and more than 7,200 detained, according to a rights group.

The country’s de facto civilian leader, Daw Aung San Suu Kyi, was arrested on the morning of the coup and is now on trial on 10 charges, including inciting public unrest and violating the Official Secrets Act. A verdict is expected on some of the charges in mid-December. Her trial also is closed to the public, and the court has ordered her attorneys not to speak to the media about the case.

Thomas H. Andrews, the U.N. Special Rapporteur on the Situation of Human Rights in Myanmar, last month urged member nations to deny the junta the money, weapons and legitimacy it needs to remain in power. He also warned of further violence and the potential for “more mass atrocity crimes.”

“I desperately hope that I am wrong,” he said.