Andrew Strempler received the sentence on Wednesday, and was also ordered to pay a forfeiture of $300,000 US and a $25,000 fine, the U.S. Justice Department said in a release.
A restitution hearing has been slated for Feb. 26.
Strempler pleaded guilty in October to conspiracy to commit mail fraud in connection with his role as owner and president of Mediplan Health Consulting Inc., a Canadian company, which also operated under the name RxNorth.com.
RxNorth was an online, mail- and telephone-order pharmacy, through which Strempler and others marketed and sold prescription drugs to U.S. residents.
Strempler, who was originally from Manitoba, was one of the first entrepreneurs in the cross-border online pharmacy industry. He was arrested in Florida in June.
The charges against him relate to a 2005 seizure of prescription drugs shipped by Mediplan.
The U.S. Food and Drug Administration claimed that many of the drugs, which were promoted as Canadian, actually came from other countries.
In a release, U.S. justice officials say Strempler obtained the medications from various contries "without properly ensuring the safety or authenticity of the drugs."
Some of the prescription drugs he sold were counterfeit, they added.
"Counterfeit prescription drugs sold through the internet pose a serious health hazard to consumers in the United States. These drugs can be adulterated, ineffective and unsafe," U.S. Attorney Wifredo Ferrer said in the release.
An FDA investigation was launched in 2006 after the agency advised consumers against purchasing several prescription drugs from Mediplan.
At that time, Strempler called the FDA warning a tactic designed to prevent uninsured Americans from getting drugs from outside the U.S.