Christos Pappas, who was second in command of the neo-Nazi former party Golden Dawn, was arrested in the Zografos neighborhood of Athens late on Thursday.
On Wednesday, he will be led before the prosecutor.
Pappas, who had been sentenced to 13 years in jail along with other leaders for forming a criminal organization, had gone missing after the verdict.
According to preliminary information, the arrest came after a counter-terrorism squad search in private home. He has been transferred to the Attica Police Headquarters (GADA), where he is in detention.