Eric Rudolph pleaded guilty Wednesday to bombing the 1996 Olympics and a US abortion clinic two years later, killing a police officer and wounding a nurse.
Rudolph, 38, also pleaded guilty to bombing a gay nightclub and two other family planning clinics and intended to bomb other targets, prosecutors said.
"Once we identified Rudolph and had him on the run, the bombings ended, saving who knows how many lives," US Attorney David Nahmias told reporters.
Rudolph, before Atlanta federal Judge Charles Pannell, pleaded guilty to the 1996 bombing of Olympic Park, in which one woman was killed and 111 people injured.
"I have deprived the government of its goals of sentencing me to death," Rudolph said in a political statement distributed afterward.
"The fact that I had entered an agreement with the government is purely a tactical choice on my part and in no way legitimates the moral authority of the government to judge this matter or to impute guilt."
Earlier Wednesday, Rudolph entered the Birmingham, Alabama courtroom of Judge Linwood Smith with a swagger, a red prison jumpsuit and a white T-shirt to face charges over the abortion clinic bombing.
While he showed respect to the judge by answering all questions directly, Rudolph seemed uninterested when details of the charges were read.
"Let me cut to the chase -- did you plant the bomb on January 29, 1998?" Linwood asked.
"Yes, your honour," Rudolph responded.
"Did you cause the bomb to explode?" Linwood asked.
"I certainly did," Rudolph responded.
Rudolph never made eye contact with the victims in the court and appeared to show no remorse.
Sentencing in both courts is scheduled for July 18, the birthday of Emily Lyon, the nurse wounded in the Birmingham blast.
In Atlanta, Greg Jones of the Federal Bureau of Investigation called Rudolph one of the FBI's "top-10 fugitives."
At the height of efforts to catch Rudolph, US officials fielded 250 federal agents, sniffer dogs and heat-seeking helicopters to flush Rudolph out of the North Carolina Mountains.
Federal officials said sympathizers in the area had protected Rudolph as a crusader and helped him elude authorities.
In May 2003, a rookie cop caught Rudolph rooting through garbage behind a food store.
The US Justice Department said Rudolph will serve four life sentences with no chance of parole in exchange for pleading guilty to all charges.
As part of the deal, Rudolph told authorities where he had hidden more than 113 kilos (250 pounds) of dynamite, including a fully built bomb, officials said.