It says Franzie Colaco, 54, promoted a tax-fraud scheme in Canada through which individuals would claim refunds equal to the value of their personal debt.
The total amount Colaco and co-conspirators swindled the Internal Revenue Service of was US$14 million, but about $8 million of that has been returned.
The Justice Department says roughly two-thirds of those filing for money they didn't deserve were Canadians who had never paid any income tax in the U.S.
Colaco, who was extradited, was convicted in July in a two-day trial and sentenced on Tuesday.
The judge cited the "audacious nature of the scheme" in imposing the sentence.