He is the last surviving member of the group responsible for the 2002 Bali bombings that killed more than 200 people.
Ali Imron, who is serving a life sentence for the attacks on nightclubs, has expressed regret for his actions, Jakarta Globe reported.
He condemned the violence brought about by the Islamic State in Syria and Iraq (ISIS) .
The terror group was responsible for the attacks in Paris two weeks ago that killed 130 people.
Imron told reporters at the Jakarta police headquarters, where he is in custody: "We still dream of establishing a country based on Islamic values, but in a good way.
"It is wrong to reach this goal through bomb attacks like we once did."
The reformed radical said the violent campaign now being carried out by ISIS does not conform to the true ideals of holy war.
Imron said: "If I ever meet ISIS members, I would explain to them that is not what jihad is.
"I am ready to advocate against ISIS if I am free."
He said he wanted to tell young militants that violent jihad should be waged only in a war zone or where Muslims were under attack.
Imron's statement came as the authorities said that about 100 Indonesians who had fought for ISIS have since returned home.
Jakarta police chief Tito Karnavian said they hope the message from a one-time radical will dissuade Indonesians from joining the terrorist organisation.
Imron, who was arrested in January 2003 while on the run in East Kalimantan, was tried and convicted of helping assemble the bombs used in the 2002 attacks, and sentenced to life in prison that September.
Since then, police have used him to help them in their counterterrorism activities.
This article was first published on November 27, 2015.
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