The sentences were largely spelled out in a plea bargain reached by the former radicals in November.
Before they were sentenced, three of the four apologized to the family of Myrna Opsahl, the bank customer who was killed by a shotgun blast during the holdup 27 years ago while depositing her church collection.
"I will be sorry for the rest of my life," said Emily Montague, 55, who was formerly known as Emily Harris. It was her that gun fired the blast.
Montague's ex-husband, William Harris, 58, addressed Opsahl's son, saying: "I've thought about your mother a lot. Your mother was never an abstraction to me. It's absolutely unacceptable that this happened."
Montague was sentenced to eight years in prison, Harris to seven years, and co-defendants Michael Bortin, 54, and Sarah Jane Olson, 55, to six years each. Olson was the only one who did not address the court.
The four had admitted to their involvement in the bank robbery, which was intended to fund the activities of the revolutionary group.
Superior Court Judge Thomas Cecil acknowledged that the Board of Prison Terms could still extend the terms agreed to by the parties, but he discouraged such an action, saying he and everyone involved had carefully considered the long history of the case in making their recommendations.
"We recognize the seriousness of the crimes that occurred in 1975," he said. But he said the prospects of the defendants are clear: "We need not guess whether these defendants will function in society. We have seen it."
He referred to their upstanding lives since then and said, "In my view and in the view of the district attorney, none of these defendants poses a danger to society."
A fifth defendant, James Kilgore, 55, is also charged in the case. After decades underground, he was captured last year in South Africa, where he had assumed a new identity and was working as a university professor.