Belal Betka pleaded guilty to engaging in hostile activity in a foreign country but claimed the trip he took with his then-wife was honourable.

During a sentencing hearing in December, he said he left after being told he had to fight for IS and because its members were mistreating civilians.

NSW Supreme Court Justice Ian Harrison on Thursday said he believed Betka's account and there was no evidence to suggest he ever held violent extremist views.

Justice Harrison told the court, sitting in Parramatta, there was no evidence the Algerian Australian was militarily trained or actively fought with Islamic State.

The Crown had argued recorded phone conversations between Betka and an un-named woman showed otherwise.

Betka allegedly spoke about the strengths of an AK-47 machine gun, said he'd "smelled death" and claimed Muslim fighters who died were 10 times better than the living.

Justice Harrison said it was "exaggerated self-promotion" and that Betka had been talking up what was a "frustratingly uneventful" time in Syria.

The Crown unsuccessfully contended that a USB flash drive containing jihadi videos which was found in Betka's bedroom showed he was a risk to the Australian community.

But Justice Harrison noted Betka hadn't been under counter-terrorism surveillance at any point since his return to Australia and the USB could have predated his travel to Syria.

Betka's excursion was neither impulsive nor opportunistic, the judge said, but he'd been "beguiled by slick advertising" and had no intention of being actively involved in the fighting.

Justice Harrison concluded the offending was "at the very lowest end of objective seriousness for offences of its kind" and he was confident Betka would never re-offend.

He sentenced Betka to three years and eight months in jail with a non-parole period of two years and nine months.

Betka is currently serving a unrelated sentence for money laundering and will be eligible for release in December 2021.

The 27-year-old was arrested at his Sydney home in December 2017 after police alleged he travelled to Syria between March and July 2015.

He was the first Australian to be charged under foreign fighter laws.

Australian Associated Press