Cosby, 81, spent his first night alone in a Pennsylvania prison after being accustomed to a life filled with handlers and household help. He could eventually be sent to a state prison that has separate units for geriatric prisoners and programs for sex offenders.
TIMELINE: Events that led to Bill Cosby's sentencing
Cosby spokesman Andrew Wyatt said Tuesday after the comedian's sentencing that Cosby was "one of the greatest civil rights leaders in the United States for over the past 50 years," while decrying the trial as the "most sexist and racist" in the country's history.
The judge, prosecutor and jury saw it differently.
"No one is above the law. And no one should be treated disproportionately because of who they are, where they live, or even their wealth, celebrity or philanthropy," Montgomery County Judge Steven O'Neill said in sentencing Cosby to an above-average sentence for a 2004 sex assault.
Cosby's defense team has raised the racial issue before, in 2016, before quickly scrapping it.
READ: Andrea Constand's full victim-impact statement made public
"We prosecute where the evidence takes us and that was done in this (Cosby) case. When (U.S.) Judge (Eduardo) Robreno released the deposition and said that this is perhaps criminal, we're obligated to look at that and we did and we worked through the case and we got to where we are today."
Cosby broke racial barriers in the entertainment world in the 1960s but later became the first celebrity of the #MeToo era to be convicted. He was found guilty in April of drugging and sexually assaulting a woman at his gated estate in 2004 after being barraged with similar accusations from more than 60 women over the past five decades.
"It is time for justice. Mr. Cosby, this has all circled back to you. The time has come," O'Neill said. He quoted from victim Andrea Constand's statement submitted to the court, in which she said Cosby took her "beautiful, young spirit and crushed it."
In her statement, Constand, 45, wrote of Cosby: "We may never know the full extent of his double life as a sexual predator, but his decades-long reign of terror as a serial rapist is over."
Cosby declined the opportunity to speak before the sentence came down, and afterward sat laughing and chatting with his defense team. His wife of 54 years, Camille, was not in court. Constand smiled broadly on hearing the punishment and was hugged by others in the courtroom.
In a blistering statement, spokesman Wyatt said the comedian was subjected to the "most racist and sexist trial in the history of the United States." Wyatt said all three of the psychologists who testified against Cosby were "white women who make money off of accusing black men of being sexual predators."
Cosby's lawyers asked that he be allowed to remain free on bail while he appeals his conviction, but the judge appeared incredulous over the request and ordered him locked up immediately, saying that "he could quite possibly be a danger to the community."
Cosby - who is legally blind and uses a cane - removed his watch, tie and jacket and walked out in a white dress shirt and red suspenders, his hands cuffed in front of him. He appeared downcast, his eyes failing to meet the camera, in a mug shot released by authorities.
Cosby must serve the minimum of three years before becoming eligible for parole.
"For decades, the defendant has been able to hide his true self and hide his crimes using his fame and fortune. He's hidden behind a character he created, Dr. Cliff Huxtable," Montgomery County District Attorney Kevin Steele said at a news conference, referring to Cosby's best-known role. But "now, finally, Bill Cosby has been unmasked, and we have seen the real man as he is headed off to prison."
Constand stood at Steele's side but shook her head to say she had no comment.
Former model Janice Dickinson, who accused Cosby of violating her, looked at him in the courtroom and said: "Who gets the last laugh, pal?"
Another accuser in the courtroom, Lili Bernard, said: "There is solace, absolutely. It is his fame and his fortune and his phony philanthropy that has allowed him to get away with impunity. Maybe this will send a message to other powerful perpetrators that they will be caught and punished."
Cosby's punishment, which also included a $25,000 fine, came at the end of a two-day hearing at which the judge declared him a "sexually violent predator" - a designation that subjects him to monthly counseling for the rest of his life and requires that neighbors and schools be notified of his whereabouts. A psychologist for the state testified that Cosby appears to have a mental disorder characterized by an uncontrollable urge to have sex with women without their consent.
Once known as America's Dad for his role on the top-rated "Cosby Show" in the 1980s, the actor was convicted of violating Constand, Temple University women's basketball administrator, at his suburban Philadelphia mansion in 2004.
Constand testified that Cosby gave her what she thought were herbal pills to ease stress, then penetrated her with his fingers as she lay immobilized on a couch. Cosby claimed the encounter was consensual, and his lawyers branded her a "con artist" who framed the comedian to get a big payday -- a $3.4 million settlement she received over a decade ago.
Five other accusers took the stand at the trial as part of an effort by prosecutors to portray him as a predator.
Cosby faced anywhere from probation to 10 years in prison. His lawyers asked for house arrest, saying he is too old and vulnerable to go to prison. Prosecutors asked for five to 10 years behind bars, warning that he could still pose a threat to women.
Women's advocates hailed Cosby's sentence as a landmark #MeToo moment.
"Bill Cosby seeing the inside of a prison cell sends a strong message that predators - no matter who they are, from Hollywood to Wall Street to the Supreme Court - can no longer be protected at the expense of victims," said Sonia Ossorio, president of the National Organization for Women of New York.
Steele said Cosby could be sent to Laurel Highlands , a state prison for lower-risk inmates on the other side of the state, about 70 miles southeast of Pittsburgh.
The AP does not typically identify people who say they are victims of sexual assault unless they come forward publicly, which Constand and other accusers have done.
Constand went to police a year after waking up in a fog at Cosby's estate, her clothes askew, only to have the district attorney pass on the case. Another DA reopened the file a decade later and charged the TV star after stand-up comic Hannibal Buress' riff about Cosby being a rapist prompted other women to come forward and after a federal judge, acting on a request from The Associated Press, unsealed some of Cosby's startling, decade-old testimony in Constand's related civil suit.
In his testimony, Cosby described sexual encounters with a string of actresses, models and other young women and talked about obtaining quaaludes to give to those he wanted to sleep with.
Cosby's first trial in 2017 ended with a hung jury.
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