Seale, 72, was convicted in June on federal charges of kidnapping and conspiracy in the deaths of Charles Moore and Henry Hezekiah Dee, two 19-year-olds who disappeared from Franklin County on May 2, 1964.
Seale showed no emotion as US District Judge Henry T Wingate read his sentence.
Wingate told Seale the crimes committed 43 years ago were “horrific” and “justice itself is ageless.” He denied a defence motion to allow Seale to be free on bond while his case is appealed.
Federal public defender Kathy Nester filed a notice of appeal.
“Mr Seale maintains his innocence to this crime,” Nester said.
During the hearing, one of Dee’s sisters and Moore’s brother talked about how the violent deaths affected them.
Thomas Moore read from a prepared statement directed at Seale.
“I hope you perhaps spend the rest of your natural life in prison thinking of what you did to Charles Moore and Henry Dee and how you ran for a long time but you got caught,” he said. “I hope the spirit of Charles and Henry come to your cell every night and visit with you to teach you what it meant by love of your fellow man.”
Wingate agreed to assign Seale to a prison where his health needs can be met. He has cancer, bone spurs and other health problems.
The prosecution’s star witness against Seale was Charles Marcus Edwards, a confessed Klansman who received immunity from prosecution for his admitted role in the abductions and his testimony.
Seale was arrested on a state murder charge in 1964, but the charge was later dropped. Federal prosecutors say the state charges were dropped because local law enforcement officers in 1964 were in collusion with the Klan.