Hisham Kassem, a former publisher and a popular Egyptian opposition figure, was released from prison on Tuesday after serving a six-month sentence, his political coalition, the Free Current, said.
The group of liberal political parties confirmed his release in a statement.
The release was also celebrated on social media by several of Mr Kassem’s friends, including activist Hossam Bahgat and rights defender Bahey El Din Hassan among others.
Mr Kassem, 65, was convicted in August of libel and slander against a former cabinet minister and for verbally assaulting officers at a police station.
The charges were widely decried as politically motivated by a number of international rights groups, including Amnesty International.
Following his sentencing in September, Mr Kassem was also fined 20,000 Egyptian pounds ($647).
Mr Kassem and the Free Current are critics of Egypt’s regime, particularly its handling of the economy, which was an area of particular focus by the coalition as it published repeated statements on how the government was mishandling its finances.
After his arrest, the Free Current said Mr Kassem was a possible candidate for the December presidential election – which ended in a third win for sitting president Abdel Fattah El Sisi.
The coalition said soon after that it would not field a candidate because “the political atmosphere will not allow for free, fair and just elections, without which the current regime becomes the competitor and the ruler, and the results become decided in advance”.
Since Mr Kassem’s arrest, Egyptian rights groups have repeatedly accused the government of eliminating viable candidates in the election.
Another presidential hopeful, Ahmed Al Tantawy, also a member of the Free Current, was convicted of illegally circulating election documents to his supporters and was sentenced to one year in prison earlier this month along with about 20 campaign staff.
His suspended sentence also included a five-year ban on running for parliamentary elections.
Also on Tuesday, prosecutors released activist and journalist Lina Attallah in exchange for 5,000 Egyptian pounds ($160) in bail.
Ms Attallah, who is editor-in-chief of the independent Mada Masr online publication, was called in for questioning on Sunday in a case filed against her last year.
She was accused of “circulating false information” and of operating a media publication without a license. The first charge is often seen in cases of opposition to the state.
The government did not immediately provide its reasoning for the decision to question Ms Attallah, long after the case was filed against her, something that several lawyers said was irregular.
A number of journalists and activists, including former BBC anchor Rasha Qandeel, decried the arrest and claimed the real reason Ms Attallah was arrested was because of a Mada Masr report that linked the Egyptian state to corruption at the Gaza border.
At Rafah, on the border with the heavily bombed enclave, Palestinian evacuees were allegedly being asked to pay up to $10,000 per person to cross into Egypt for safety or medical treatment.
The Egyptian State Information Service denied the allegations last week and said there were no such transactions taking place.
