Canada's self-proclaimed "Prince of Pot" has been sentenced to five years in U.S. prison for selling marijuana seeds to customers south of the border.

Longtime Vancouver cannibis crusader Marc Emery was handed the decision in a Seattle District Court Friday afternoon. The ruling included four years of supervised release for the 52-year-old once he finishes his jail term.

U.S. authorities maintain that Emery was the country's largest supplier of marijuana seeds for more than a decade until his 2005 indictment for conspiracy to manufacture marijuana, and that his activities were linked to illegal grows operations across America.

Emery claimed what he was doing wasn't illegal because he was only selling the marijuana seeds, not the plants.

At sentencing, U.S. District Judge Ricardo S. Martinez disagreed, telling him "there is no question your actions were illegal and criminal and your actions ensured that others broke the law and suffered the consequences."

U.S. Attorney Jenny Durkan said Emery believed the laws didn't apply to him.

"[He] put his personal profits above the law. He made millions of dollars by shipping millions of seeds into the U.S. He sold to anyone who would pay him -- with no regard for the age or criminal activities of his customers. Now, Emery is paying the price for being part of the illegal drug trade that damages lives, homes and the environment."

Emery was extradited to the U.S. in May.

In a plea agreement, he admitted he operated a seed distribution business, Marc Emery District, selling seeds to customers across the U.S. He also operated a retail store in Vancouver's Gastown neighbourhood, as well as filling mail and telephone orders.

Prosecutors said Emery sold seeds to undercover Drug Enforcement Administration (DEA) agents multiple times in 2004 and 2005.

Two of his employees, Michelle Rainey, 39, and Gregory Keith Williams, 54, were sentenced to two years of probation for conspiracy to manufacture marijuana.