Cosby in 1965 became the first black actor to land a leading role in a network drama, "I Spy," and he went on to earn three straight Emmys. Over the next three decades, the Philadelphia-born comic created TV's animated "Fat Albert" and the top-rated "Cosby Show," the 1980s sitcom celebrated as groundbreaking television for its depiction of a warm and loving black family headed by two professionals, one a lawyer, the other a doctor.
He was a fatherly figure off camera as well, serving as a public moralist and public scold, urging young people to pull up their saggy pants and start acting responsibly.
Constand, who worked for the women's basketball team at Temple, where Cosby was a trustee and proud alumnus, said she was assaulted after going to his home in January 2004 for some career advice.
Then-District Attorney Bruce Castor declined to charge Cosby, saying at the time that the comedian and his accuser could be portrayed in "a less than flattering light." Constand eventually settled a lawsuit against Cosby in 2006 on confidential terms.
Her allegations and similar ones from other women in the years that followed did not receive wide attention at the time but exploded into view in late 2014, first online, then in the wider media, after comedian Hannibal Buress mocked the moralizing Cosby as a hypocrite and called him a rapist during a standup routine.
That opened the floodgates on even more allegations.
The women were mostly from the world of modeling, acting or other entertainment fields, and Cosby or his representatives denied their allegations, accusing some of them of trying to extract money from him or get ahead in show business.
Earlier this year, The Associated Press persuaded a judge to unseal documents from the Constand lawsuit, and they showed the long-married Cosby acknowledging a string of affairs and sexual encounters.
Cosby, a longtime resident of Shelburne Falls, Massachusetts, testified that he obtained quaaludes in the 1970s to give to women "the same as a person would say, `Have a drink."' He denied giving women drugs without their knowledge.
In his deposition, Cosby said he gave Constand three half-pills of Benadryl for stress, telling her only that they were her "friends." He said he fondled Constand, taking her silence as a green light.
"I don't hear her say anything. And I don't feel her say anything. And so I continue and I go into the area that is somewhere between permission and rejection. I am not stopped," Cosby testified. He said Constand was not upset when she left.
Prosecutors said Cosby used wine and drugs to render her incapable of resistance after "the much younger, athletic" Constand blocked two previous sexual advances.
Constand's lawyer has said Constand is gay and was dating a woman around the time she met Cosby in the early 2000s. The AP generally does not identify people who say they have been sexually assaulted unless they agree to have their names published, as Constand has done.
Cosby's fall has been especially painful to many blacks who regarded his commercial and cultural success with great pride.
"There is a fatal difference now between Cliff Huxtable and Bill Cosby that can never be overcome," said author and professor Michael Eric Dyson, who wrote a book on Cosby a decade ago. "It does add a creepy subtext and a shadow of tremendous moral weight that will inevitably be brought up each time his name is evoked."