US lawyer Andrew Branson said on Wednesday he had appealed to a Turkish court over the sentence last week that his client had been jailed for terrorism charges.
Branson was the focus of a diplomatic crisis that contributed to the lira decline this year.
He was sentenced to more than three years in prison for helping terrorist organizations, but was allowed to return to the United States and met President Donald Trump.
A journalist near the courtroom where the decision to launch Branson in Izmir was described earlier this month as "the most expensive prisoner in Turkey."
It seems that this description is more accurate of the situation, after the Turkish President Recep Tayyip Erdogan concessions in the framework of a deal with the United States.
According to the views of observers, Branson's three-year prison sentence was only a formality, to beautify his release and to show him as a purely judicial matter, but in fact the political interference in the case appears to be clear, especially since the judgment is detailed to have already been implemented so that Branson can leave His imprisonment, the whole of Turkey, immediately, something that has already happened.
For the lawyer, a copy of his application, seen by Reuters, said the reason for the appeal was "contrary to law and procedure."
The prosecution also challenged the judgment for the same reason as provided in a copy of his application.
The priest has been accused of ties to Kurdish militants and supporters of Turkish-born Turkish cleric Fathullah Gulen, who is accused by Ankara of a coup attempt in 2016.
Branson, 50, has been living in Turkey for more than 20 years.
Relations between the two NATO allies are strained over US support for Kurdish fighters in northern Syria, Turkey's plans to buy a Russian missile defense system and a US jail for an executive of a Turkish state bank over a sanctions case against Iran.
Branson's release could help ease tensions between Ankara and Washington, but political analysts say many problems remain, including Washington's request for the release of other US citizens and staff jailed in Turkey.
According to reporters accompanying US Secretary of State Mike Pompeo, who is in Ankara on Wednesday, he met the families of three Turkish employees of the US diplomatic mission who were arrested after the attempted coup.
