But the sentencing likely isn't the end of the story. Prosecutors said they could charge Peterson in the disappearance of his fourth wife, who vanished when she was 23. An appeal also awaits, and defense attorneys believe the conviction could easily get tossed, in part because prosecutors heavily relied on hearsay evidence.
"It has a good a chance of a successful appeal as any case I've ever seen," Steve Greenberg, one of Peterson's attorneys, said late Thursday.
Illinois does not have the death penalty, and the 59-year-old Peterson had faced a maximum 60-year prison term. Judge Edward Burmila gave him four years' credit for time he has served since his 2009 arrest.
Before the sentence was announced, Peterson started his statement to the judge with a startling scream — then went on for 30 more minutes, continuing in mostly hushed tones, crying and trying to regain his composure at times. His voice quivered and his hands were shaking as he reached for a glass of water.
"I loved Kathy. She was a good mom," he said, tearing up. "She did not deserve to die. But she died in an accident."
At times, Peterson seemed to wallow in self-pity, telling the judge tearfully: "I don't deserve this." Another time, he seethed, blaming prosecutors for what he called "the largest railroad job ever" in his case.
Minutes later, Peterson glared at Glasgow and challenged him to look him in the eyes. Glasgow, who had been taking notes, laid down his pen, folded his arms and looked straight back at Peterson. "Never forget what you've done here," Peterson said.
Glasgow later told reporters about that moment, saying, "I was thinking, 'You're a cold-blooded murderer and I'll stare you down until I die.'"