Christos Pappas, the second-in-command of the neo-fascist Golden Dawn party, was one of 15 members of the group who were arrested during the weekend.
Pappas arrived by taxi to the Greek Police headquarters in Athens to turn himself in, Ekathimerini.com reported.
As he walked into the headquarters, he turned toward a crowd of supporters, gesturing to them in what was interpreted as a Nazi salute, the website said.
"They won't break us. Long live Golden Dawn," he shouted.
Fourteen other members of the group, including its leader, Nikos Mihallkiakos, were arrested Saturday. They were charged with forming a criminal organization with intent to commit crimes. Pappas faces the same charges.
The government said last week it had begun a probe into whether members of the violent organization had infiltrated the country's police and military forces.
Golden Dawn has 18 members in Parliament and is the third-most popular party in Greece.
Human rights groups say Golden Dawn has terrorized immigrants and police have ignored their violence.