Melbourne based Adam Brookman voluntarily returned to Australia under police escort late Thursday. He surrendered to authorities in Turkey.
Brookman who appeared in a Sydney court via video link from the Surry Hills Police Centre will be extradited to Victoria.
In Parramatta Court, members of the Melbourne Joint Counter-Terrorism Team applied for his extradition.
According to media reports, Brookman wanted to use his medical skills for humanitarian work, but eventually fled from Islamic State because of its violence.
His lawyers have been in negotiations with the Australian Federal Police (AFP) about his return since April.
The AFP confirmed it had managed Brookman's travel back to Australia, but he has not yet been charged.
It said he was facing several investigations.
"If there is evidence an Australian has committed a criminal offence under Australia law while involved in the conflict in Syria and Iraq, they will be charged and put before the courts," an AFP spokesman said.
Media reports also claimed that the father of five claimed Brookman was forced to join ISIS after being injured in an air strike and sent to a hospital under ISIS control which he was barred from leaving.