Agim Ajazi, 34, faced Brisbane Supreme Court on Tuesday for sentencing after pleading guilty in May to foreign incursions, engaging in hostile activities and advocating terrorism.
Ajazi left Australia in July 2013, establishing a base in Turkey from which he crossed the border into Syria the following year, prosecutors said in May.
The former Gold Coast resident was not a member of a terrorist organisation, but admitted taking part in efforts to overthrow the Syrian government as an infantry fighter who fired an Kalashnikov assault rifle during battles that caused hundreds of casualties.
Ajazi told a Melbourne-based journalist at the time that he found the battles ""quite fun (and) thrilling".
Justice Susan Brown accepted that Ajazi between 2014 and 2016 had fought alongside groups proscribed as terrorist organisations by the Australian government such as Jabhat al-Nusra, which was closely aligned with al-Qaeda.
Ajazi also fought alongside groups that were not officially defined as terrorists.
"(Ajazi) made social media posts ... which referred to the events in Syria and his involvement in the conflict. The posts promoted an extremist Islamic ideology," Justice Brown said in sentencing remarks.
She also accepted that Ajazi had intentionally advocated a terrorist act by threatening on social media to kill Russians in the United States.
Russia at the time was supporting the Syrian government through heavy air strikes against rebel and terrorist groups.
Defence barrister Glen Rice said in May that Ajazi no longer has extremist views but had been inspired to travel to the war zone at the start of the Syrian conflict.
"He was particularly motivated by images which were available on the internet of the kind of treatment that that regime dealt its citizens," Mr Rice said.
Ajazi faced a possible maximum sentence of life in prison under Australia's laws targeting people who travelled overseas to act as foreign fighters.
Justice Brown accepted that Ajazi was a low-level foot soldier, did not intend to commit or promote terrorist acts in Australia and that his social media posts were influenced by immature boasting.
"The posts are still of a serious nature and reflect that the defendant was radicalised at the time and committed to the hostile activity he was involved in," Justice Brown said.
She sentenced Ajazi to eight years and two months in prison with a non-parole period of six years, one month and two weeks.
Justice Brown declared Ajazi had already served 1295 days in custody, including in South Australia and a year spent detained in Turkey.
"I am also required to warn you ... that an application may be made for a continuing detention order requiring you be detained in custody after the end of your sentence or an extended supervision order," she said.
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