Ramanan Mylvaganam appeared before a federal judge in Brooklyn on Monday for his sentencing.
The Mississauga man was first taken into custody in Canada in 2006 while he was a computer engineering student at the University of Waterloo.
He pleaded guilty in February to conspiring to provide material support to a foreign terrorist organization.
He admitted he sought to obtain about $22,000 worth of submarine design software and night vision equipment for the separatist group, designated by the United States as a terrorist organization in 1997 and by Canada in 2006.
Three other suspects with ties to the University of Waterloo and the Tamil Students Association were among a dozen men charged in 2006.
The arrests followed a joint investigation by the FBI and the RCMP into an alleged plot to buy weapons, launder money through front charities and smuggle equipment to the rebel group.
In appealing his extradition, Mylvaganam didn't dispute the charges against him.
Instead, he argued the evidence didn't support the extradition judge's conclusion that he acted with "requisite knowledge and intent to support or participate in terrorist activity."
The Ontario Court of Appeal upheld the extradition order, ruling that Mylvaganam very likely knew he was assisting the group.
Sri Lankan government forces defeated the Liberation Tigers of Tamil Elam in 2009, a month before the court ruled on Mylvaganam's extradition.