The mother-of-one, who travelled to Syria and became a “propaganda tool” for the terror group, had the sentence handed down at the Special Criminal Court today.
Mr Justice Tony Hunt said the court would make allowance for any time she had already spent in custody.
In May, Smith (40), from Dundalk, Co Louth was found guilty after a non-jury trial of being a member of the Islamic State group between October 28, 2015 and December 1, 2019.
She was acquitted of a second charge of financing terrorism by sending money to a man in May 2015, for the benefit of IS. She had denied both counts.
The court heard Smith converted to Islam after years of conversing online with a leading American ISIS propagandist, John Georgelas.
She left the Irish Defence Forces and later travelled to Syria during the country's civil war, in answer to terrorist leader Abu Bakr al-Baghdadi’s call to Muslims to join the caliphate.
Smith married British jihadist Sajid Aslam and became part of the "life blood" of ISIS as a propaganda tool and as a woman who would help to build the Islamic State, the court heard.
Prosecutor Sean Gillane said while she was not involved in combat, she had “enveloped herself in the black flag of IS.”
When the caliphate collapsed in 2019, Smith fled with her daughter and ended up in Syrian refugee camps before being deported to Ireland from Turkey.
Smith denied aiding the terror group and her defence was that she had travelled to Syria out of religious obligation.
In its verdict in May, the three-judge court found Smith had travelled to Syria "with her eyes open" and pledged allegiance to the organisation led by terrorist leader al-Baghdadi.
At a sentence hearing two weeks ago, Smith's defence described her as a "very damaged” and "vulnerable person" who suffered from mental health issues and was “looking for answers” when she converted to Islam.
In her quest for knowledge she "did not fully appreciate that her mentor's views were not the norm,” her barrister Michael O’Higgins said.
She had also suffered a violent and abusive marriage, he said. Mr O’Higgins argued that Smith's time spent in custody in Syria should offset any jail term here.
More to follow…