Eric Rudolph faced victims and relatives in an Atlanta courtroom and said he regretted his actions.
"I can't begin to truly understand the pain that I have inflicted on these innocent people. I would do anything to take that night back, and to those victims, I apologise," he said.
Rudolph said he had hoped only to embarrass the US government when he planted the nail bomb to protest against abortion in Centennial Olympic Park on 27 July 1996.
"I sincerely hoped to achieve my objectives without harming innocent civilians," Rudolph said before he was led away to serve four life sentences plus 120 years in a maximum security prison in Colorado for a series of bombings including the Olympics blast and two other bombings in the Atlanta area.
Last month he was sentenced to life in prison for an explosion at an abortion clinic in Birmingham, Alabama, which killed a police officer and critically injured a nurse.
Rudolph agreed this year to plead guilty to the three Atlanta explosions as well as an abortion clinic bombing in 1998 in a plea bargain with federal prosecutors, who agreed to drop the death penalty. He will not be eligible for parole.
Rudolph's victims told the court that they wanted him to suffer for ever.
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