From American cultural icon blazing past racial barriers to prison for aggravated indecent assault: a judge's sentencing on Tuesday saw "America's Dad" Bill Cosby reduced to a sexually violent predator in handcuffs.

It was a name that once evoked so much - treasured father figure, a seemingly model citizen with gentle, self-deprecating comedy and a playful voice that would go from deep to screeching for a laugh.

But that legacy was buried forever on Tuesday when a judge sentenced him to a minimum of three, and a maximum of 10, years in prison for drugging and molesting a former basketball player at his Philadelphia mansion 14 years ago.

The first African-American actor to grace prime-time American television and the man who personified upper-middle-class black family bliss on television is now a frail sex offender headed to a state prison.

Only five years ago, his cultural influence was once so great that chat-show queen Oprah Winfrey credited the now 81-year-old Cosby with helping to pave the way for America's first black president, Mr Barack Obama.

The Cosby Show - which ran from 1984 to 1992 - "introduced America to a way of seeing black people and black culture that they had not seen before", she proclaimed in 2013.

Then this April, a Pennsylvania jury convicted him and a yelling Cosby called the district attorney an "a**hole" in open court - as far from his once squeaky-clean public persona as you could imagine.

On Tuesday afternoon, he was led out of court in handcuffs, stripped of his suit jacket and tie, driven to a county correctional facility, before being processed by the Pennsylvania state prison system.

It was the final ignominy after years of scandal. When comedian Hannibal Buress took to the stage in 2014 to tell Cosby to stop moralising to African-Americans and accused him of being a "rapist", the floodgates opened.

About 60 women, many of them one-time aspiring actresses and models, came forward publicly to brand him a calculating, serial predator who plied victims with sedatives and alcohol to bed them over four decades.

But only one case had not surpassed the statute of limitations: that of Ms Andrea Constand.

Both a first and a second trial in Norristown, Pennsylvania, revealed a dark underside to his signature role of benevolent father figure and affable obstetrician Cliff Huxtable on The Cosby Show.

"Everybody knows you, Mr Cosby," said a police officer taking down his original deposition.

"Not really," came the elusive reply.

Born on July 12, 1937 in Philadelphia to a maid and a Navy cook, William Henry Cosby Jr quickly emerged as the class clown and joined the United States Navy after 10th grade, finishing high school by correspondence.

He won an athletic scholarship to Temple University and started doing stand-up gigs.

In his early 20s, he appeared on variety programmes, but got his first big break in 1965, when he co-starred in the espionage thriller I Spy. It was a pivotal moment when few black actors had starring roles. He won three Emmys and went on to star in a string of successful movies in the 1970s.

Then from 1984 to 1992, he portrayed Huxtable, the affable, funny dad with a lawyer wife in The Cosby Show - so named thanks to his star power.

The sitcom was a fabulous success, turning Cosby into a major figure of American pop culture in the second half of the 20th century.

He was showered with awards for the show, which anchored NBC's powerful Thursday night line-up and for the first time put an affluent African-American family on prime-time, turning him into an instant role model.

Along the way, he authored best-selling books and was for decades a member of the Temple board of trustees until he resigned in 2014, stripped of honorary degrees as sexual assault scandals mushroomed.

Comedian friends like Whoopi Goldberg who once supported him denounced him.

But not once has Cosby publicly expressed any remorse.

In a public relations offensive before his first trial, and claiming to be legally blind, he suggested that racism played a role in his legal woes, insisting he still wanted to write and perform.

Cosby did not testify at trial. Through it all, his wife of more than half a century, Camille, has publicly defended him.

The couple had five children. Their son Ennis was shot dead in 1997 while changing a tyre in California and daughter Ensa died of renal disease in February.

AGENCE FRANCE-PRESSE