Following a four-week trial, a jury of eight men and four women found 56-year-old Hamza guilty on all 11 counts he faced. The cleric could face life in prison when he is sentenced in September.
Hamza came to prominence in the UK for his fiery sermons outside Finsbury Park mosque; in one he praised the 11 September hijackers.
Speaking briefly to reporters, US Attorney Preet Bharara said the verdict proved once again that the US justice system can handle high-profile terrorism trials.
“Abu Hamza attempted to portray himself as a preacher of faith,” he said. “He was, instead, a trainer of terrorists.”
Hamza testified in his own defence, denying he sent anyone to Oregon or Afghanistan and claiming he became involved in the kidnapping only after the fact, when he offered to negotiate a peaceful resolution.