Mohamed Ibrahim Ahmed, a 38-year-old resident of Sweden, received his 111-month sentence in a New York City federal court, said Preet Bharara, U. S. Attorney for the Southern District of New York.
Ahmed traveled to Somalia to receive military training from the terror group, federal officials said. Al-Shabaab has made several public statements threatening to harm the United States.
"Mohamed Ibrahim Ahmed traveled thousands of miles to align himself with al-Shabaab, to aid their campaign of terror and to learn their 'ways of war,'" Bharara said in a statement. "Today, his journey ends in prison and marks the latest victory in our constant effort to protect Americans from terrorism at home and abroad."
In addition to the prison term, Ahmed will be deported upon completion of his sentence, prosecutors said.
Ahmed pleaded guilty last June to one count of conspiracy to provide material support to the terrorist organization Al-Shabaab and one count of conspiracy to receive military-type training from it, prosecutors said.
In a March 29, 2012, letter to a federal judge, prosecutors said a former top leader of Al-Shabaab may have testified against Ahmed if his case were to go to trial.
That former leader is Ahmed Abdulkadir Warsame, who also had ties to al Qaeda and who secretly pleaded guilty in 2011 to federal charges, the Justice Department said Monday. He has provided the U.S. government with valuable intelligence information, the Justice Department said.
The U.S. military captured Warsame at sea in April 2011 while he was traveling from Yemen to Somalia. He pleaded guilty in New York the following December to nine terrorism charges.
Al-Shabaab has tried to destabilize the government of Somalia in a "holy war" and has recruited foreign fighters from other countries, including the United States, to engage in violent jihad, prosecutors said.
Ahmed was arrested in Nigeria in 2009 after authorities say he traveled to Somalia to undergo bomb-making and bomb-detonation training from members of Al-Shabaab, authorities said.
While he was in Somalia, Ahmed paid 3,000 euros (about $3,830) to Al-Shabaab and gave an AK-47 rifle and magazines to a military commander in the group, according to court documents.