In January, Pham admitted three counts of terrorist-related activity based on his support for the group though he denied that he ever intended to carry out his plot or harm anyone. No attack ever occurred.
The former Vietnamese national was first arrested in the UK in June 2012 and was extradited to the US in early 2015.
He pleaded guilty to one count of providing material support to AQAP, one count of conspiring to receive military training from AQAP and one count of possessing and using a machine gun in furtherance of crimes of violence.
District Judge Alison Nathan said Pham deserved an “exceptionally severe sentence” after he became a trusted asset for the terrorist group.
He worked as a graphic artist on its magazine, Inspire, that was said to be used by the Boston marathon bombers to learn how to make bombs.
Scotland Yard’s Counter Terrorism Command provided evidence in the case
During the hearing Pham said he had made a “terrible mistake” that he regretted, sending a letter to the judge to say he renounced all acts of terrorism and extremist ideology.