It is unclear when Mahmoud Hussein will be released from prison. Gamal Eid, the executive director of the Arabic Network for Human Rights Information, said that under Egyptian law he should be released from prison within 24 hours.
"This is a final court ruling but the problem is that security forces tend to delay releases when they do not like those freed," said Eid.
Hussein, who was detained in 2016, was being held on charges of spreading false news, joining a banned group and receiving foreign funds, his lawyer Taher Abou Nasr said.
Zahra Hussein, the journalist's daughter, announced her father’s release with a social media post that said: “Dad has been freed, thank god.”
At the time of his arrest, Hussein was in Egypt on holiday.
Another Al-Jazeera journalist, Abdullah Shamy, who was imprisoned in Egypt between 2013 and 2014, wrote on Twitter that Hussein has been released with “precautionary measures” although the measures have not been clarified by the court.
Cairo accuses Qatar of supporting the Brotherhood, which the country branded as a terrorist group in 2013. The Brotherhood says it is a peaceful group.
Rights groups accuse the government of President Abdel Fattah al-Sisi of a sweeping crackdown on dissent, which they say is the worst ever for Egypt.
Since 2013 when Sisi took power, thousands of Islamist opponents, as well as scores of liberal activists and journalists, have been imprisoned by the authorities.
In February, the United Nations called Hussain’s imprisonment “arbitrary detention.”