Former Florida university professor Sami al-Arian was sentenced to four years and nine months in prison on Monday for aiding the Palestinian group Islamic Jihad.
US District Judge James Moody sentenced al-Arian to the maximum 57 months in prison but gave him credit for 38 months he has already served. He will have to serve the balance, 19 months, before being deported, prosecutors said.
Al-Arian, 48, was arrested in February 2003 on charges he gave money and support to the Palestinian Islamic Jihad, which has been designated a terrorist organisation by the United States.
The case against al-Arian was considered a key test of the US government's surveillance powers, which were strengthened by the Patriot Act following the September 11 attacks on the United States. The case was built on thousands of hours of wiretapped phone calls and intercepted e-mails gathered over a decade.
Al-Arian was acquitted on eight of the 17 charges against him last December after a six-month trial with three co-defendants.
On April 14, al-Arian pleaded guilty to a single count of conspiracy to provide services to the PIJ and agreed to be deported. In return, federal prosecutors agreed to drop the remaining eight charges against him.
It was not certain where al-Arian will be sent when he is deported. His parents are Palestinians but he was born in Kuwait and grew up in Egypt.
In his ruling, Moody harshly criticised al-Arian for doing nothing to stop bombings perpetrated by Islamic Jihad. "You lifted not one finger. To the contrary, you laughed when you heard of the bombings," he said.
"You are a master manipulator. The evidence is clear in this case. You were a leader of the PIJ."
In a brief statement before he was sentenced, al-Arian praised the US justice system and said he was grateful for the opportunities America had provided his family.
"The American chapter in my life is about to close," he said, adding, "I'm very proud of my contributions."
Al-Arian was a professor at the University of South Florida in Tampa from 1986 until his arrest in 2003, when he was fired.
When he was arrested, then-Attorney General John Ashcroft described him as the North American leader of the Islamic Jihad and said the group was responsible for over 100 deaths in Israel, including two Americans.
Al-Arian is married and has five children, who are all US citizens because they were born here. The three oldest children are adults and are expected to stay in the United States.