Mark Taylor, the "Kiwi Jihadist" has been jailed in a Kurdish prison after surrendering after life became unbearable, reports say.
ABC News Australia reported the New Zealander, who had lived with the extremist group for five years, handed himself over after leaving because of lack of resources.
"There was no food, no money; basic services were pretty much collapsed. I was in a pickle myself and had to make a final decision, which was to leave," ABC News reports.
The US marked Taylor a global terrorist in 2015 after he appeared in an IS propaganda video and encouraged attacks in Australia and New Zealand.
He said for the five years he was with the group he was never a fighter, but had been deployed as a guard.
"I was helping to guard a border between the Syrian Government and the Islamic State," he told ABC News.
"There's a difference between fighting and guarding. Guarding you don't need to plan anything; attacking you need to make preparations."
In 2009 he was arrested in Pakistan for trying to gain access to Al Qaeda.
He also spent 50 days in an IS prison after forgetting to turn off a geo-tagging function on a tweet, giving away his location.