From US cultural icon blazing past racial barriers to tainted pariah on trial for sexual assault: a hung jury may have given Bill Cosby momentary relief, but it is not likely to help restore his image in America's eyes.

His name 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 in search of a laugh.

But that legacy has been forever tarnished by a jury that did not convict him, but also did not acquit him on three counts of aggravated indecent assault for drugging and molesting a former university employee at his Philadelphia mansion more than 13 years ago.

The first African American actor to grace prime-time US television and the man who brought upper-middle-class black family bliss to television is now frail, isolated and facing the prospect of a retrial.

So great was his cultural influence that chat show queen Oprah Winfrey credited the now 79-year-old Cosby with helping to pave the way for America's first black president, Barack Obama.

In 2013, she said "The Cosby Show" -- which ran from 1984-92 -- "introduced America to a way of seeing black people and black culture that they had not seen before."

Just over a year later, his name was mud. When comedian Hannibal Buress took to the stage in 2014 to tell Cosby to stop moralizing to African Americans and accused him of being a "rapist," the flood gates opened.

Around 60 women, many of them formerly 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.

- Everybody knows -

But only one case had not surpassed the statute of limitations: the alleged assault of Andrea Constand, for which the Emmy- and Grammy-winner may yet be convicted and face prison time.

The 11-day trial in Norristown, Pennsylvania alleged 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 in the case.

"Not really," came the elusive reply.

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

He won an athletic scholarship to Temple University and started doing stand-up comedy. In his early 20s, he appeared on variety programs, 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 of an upper middle class black family with a lawyer wife in "The Cosby Show" -- so named thanks to the actor's overwhelming star power.

The sitcom was a fabulous success, becoming the ultimate family-oriented series, turning Cosby into a major figure of US pop culture in the second half of the 20th century.

- Shadow -

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.

On Saturday, his defense lawyer Brian McMonagle said "justice is real" and welcomed the mistrial.

But Cosby himself stood in silence, his head bowed, a shadow of the charismatic, ebullient figure synonymous with squeaky clean humor, social progress and the American dream.

In a pre-trial public relations offensive, he suggested that racism may have played a role in his legal woes, in an somewhat rambling and confused radio interview.

"'Nefarious' is a great word," he told Sirius XM, insisting that despite turning 80 in July, he still wants to write and perform.

But at trial, he declined to testify. His legal team brought just one witness to the stand, before resting their case minutes later.

His wife of 53 years, Camille, has stood by his side. The couple have five children. Their son Ennis was shot dead in 1997 while changing a tire in California.