Lawal Olaniyi Babafemi, 33, traveled from his home country to Yemen where he took direct orders from now-deceased terror leader Anwar al-Awlaki, prosecutors said.
The FBI said Babafemi used his English language skills to help produce al-Qaida's Inspire magazine.
Babafemi also received weapons training while in Yemen.
“The defendant traveled to Yemen to put himself at the disposal of a violent terrorist organization,” said U.S. Attorney Loretta Lynch.
Lynch said he traveled to Yemen three times to meet and train with terror leaders. He was paid $9,000 in cash to “recruit others to join the terrorist group.”
Babafemi faces up to 30 years in prison when he is sentenced by Judge John Gleeson on Aug. 27.