The Swede, 37, was sentenced to four years in prison by a court in the state of Washington, the United States Department of Justice said in a statement.
The man is believed to have taken in $71 million in a series of scams which reportedly victimized approximately 960,000 innocent computer users.
The 37-year-old was also ordered to pay $650,000 in forfeiture.
“Payment processors like this defendant are the backbone of the cybercrime underworld,” said US Attorney Durkan.
“As an established businessman, this defendant put a stamp of legitimacy on cyber criminals. He was involved in defrauding thousands of victims, and his actions contributed to insecurities in e-commerce that stifle the development of legitimate enterprises and increase the costs of e-commerce for everyone.”
The man was arrested in Denmark in January this year and extradited to the United States in March. He pleaded guilty in August to one count of conspiracy to commit wire fraud and one count of accessing a protected computer in furtherance of fraud.
The Federal Bureau of Investigation (FBI) led the investigation with help from authorities in Sweden, Denmark, the UK, France, Germany, Romania, Lithuania, Latvia, Ukraine, the Netherlands, Cyprus and Canada.
“Partnerships are central to the FBI in accomplishing its mission,” Special Agent in Charge Laura M. Laughlin said in the statement.
She added her thanks to the FBI’s foreign partners, and pledged an ongoing commitment to the case.
“The FBI and its partners will continue to work tirelessly until we bring in the remaining perpetrators of this malicious scheme,” she said.
The prosecution of the Swede is part of Operation Trident Tribunal, an ongoing, coordinated enforcement action targeting international cybercrime.
Scareware is malicious software that tricks computer users into paying for unnecessary anti-virus software to remove it. The scareware is created to shock and threaten the computer owner, often aggressively, until money is transferred.
Computer users are advised to only download software from brands they know and trust, and to avoid software promoted through constant pop-ups that can be difficult to dismiss.