Khaled al-Fawwaz, who was convicted earlier this year, was sentenced yesterday in New York.
The attacks in Kenya and Tanzania killed 224 people, including a dozen Americans.
Fawwaz’s lawyer, Bobbi Sternheim, had asked that he be sentenced to less than life, saying he was less culpable than others.
But prosecutors said Fawwaz was an al-Qaeda leader who had helped bin Laden make sure his 1996 declaration of war against the US reached the world. They said he also led a terrorist training camp and a terror cell.
Fawwaz, 52, turned towards victims of the bombings and spoke shortly before his sentence was announced.
“I can’t find words to describe how terribly sad and sorry I am,” he said. “I don’t support violence… I hope one day people will find other ways to live with their differences other than violence.”
US District Judge Lewis Kaplan announced Fawwaz’s sentence after the court heard from three victims, including Ellen Karas, who was left blind by the attack in Nairobi. “I worship the same God as you,” she told Fawwaz. “But he is not an angry God. He is not a vengeful God.”
Edith Bartley, whose father and brother died in the Nairobi blast, said the attacks had caused her “unbearable pain and sorrow”.
“Mr al-Fawwaz, you are a travesty to the human race,” she said.
During the trial, assistant US attorney Sean Buckley told jurors Fawwaz was No 9 on a list of al-Qaeda members that was recovered by American special forces from an al-Qaeda leader’s home after the 11 September attacks in 2001.
Mr Buckley said yesterday that Fawwaz was the last of the men who had been arrested in the case to face trial.
The Saudi Arabia-born Fawwaz was arrested in London weeks after the August 1998 attacks at the request of the US but was not extradited from Britain until 2012.
He had been scheduled to stand trial with Abu Anas al-Libi, who was snatched off the streets of Libya in 2013, but Libi died in January after a long illness.
Another co-defendant, Egyptian lawyer Adel Abdul Bary, was sentenced in February to 25 years in prison after he pleaded guilty in what Judge Kaplan called an “enormously generous plea bargain” that will enable him to be freed in about eight years.
After Fawwaz’s trial in February, Preet Bharara, the US attorney for the southern district of New York, said the defendant had “played a critical role for al-Qaeda in its murderous conspiracy against America”.
There were a dozen Americans among the dead after US embassies in Kenyan capital Nairobi and Dar-es-Salaam in Tanzania were bombed in 1998.
Mr Bharara described Fawwaz as one of Bin Laden’s “original and most trusted lieutenants” who had been the leader of an al-Qaeda training camp in Afghanistan and later acted as bin Laden’s “media adviser” in London. One of his roles, Mr Bharara said, was to ensure bin Laden’s threats against the US were distributed and noticed across the globe.
“Murderous words lead to murderous action,” assistant US attorney Nicholas Lewin told jurors.