The court convicted the 18-year-old of belonging to a terrorist organization.
His defense argued that he was traumatized as a child by fighting in Chechnya.
The Austria Press Agency cited the offender Tuesday as saying he was radicalized in prison while serving a 14-month sentence for robbery and other offenses that ended last year.
He said that he was in contact with an uncle who was fighting in Syria.
The prosecution cited him as telling that relative that "we will see each other soon by Allah." But the man testified he never had any intention of joining him.
The man was not identified in keeping with Austrian privacy laws.