Ali Amin, 17, of Manassas, was the first minor prosecuted by the United States in such a case. US District Judge Claude Hilton handed down a 136-month sentence in a hearing in Alexandria, Virginia, the department said in a statement.
Amin pleaded guilty in June to using Twitter and his blog to provide instructions on how to use the virtual currency Bitcoin to send funds to the militants.
Prosecutors said Amin also helped another Virginia resident, Reza Niknejad, to travel to Syria to join the Islamic State. The group has taken control of areas of Iraq and Syria in a campaign marked by mass killings and beheadings.
The SITE monitoring service, which follows social media postings by jihadist militants, has said Amin had some 4,000 Twitter followers and was in communication with well-known Islamic State fighters and recruiters.