Ms Jackson and two associates had been accused of demanding $40m (pounds 25m) from Mr Cosby against threats to expose him to the media as her natural father. She was convicted of extortion, conspiracy and crossing a state border in order to commit a crime. Her two associates were also convicted.
On hearing the verdict, after a three-week trial during which Mr Cosby had appeared in person, Ms Jackson broke down in tears, sobbing to her lawyer: "How could they?"
On the face of it, the case against Ms Jackson, which was backed up with recordings of telephone threats and demands made to Mr Cosby's lawyers, was open and shut. She had demanded money from Mr Cosby with menaces. In practice, however, it was far more complicated. As her lawyer argued, she had grounds for believing that she was indeed Mr Cosby's daughter. Mr Cosby admitted to having a fling with her mother around the time she was conceived and had paid towards her upkeep. Ms Jackson alleged that this was "hush-money", intended to silence her mother.
Mr Cosby, who says these contributions were gifts similar to those he has made to a number of young black people, denies paternity, but has consistently refused to take a blood test. The judge ruled that whether or not he was her father was irrelevant to the extortion charge against her. It is this that has split America.
Some believe that the fact or not of Mr Cosby's paternity is crucial to the case. Others believe that extortion is extortion, whether or not the threatened expose is true. While Mr Cosby has won the case on that principle, the question of his paternity could be reconsidered during the sentencing hearing which is likely to be held next week. At stake is his image as television's ideal father - an image, in an America hungry for black family role models, that has made him very rich.
Earlier this year, Mr Cosby's son, Ennis, was murdered, after breaking down on a road in California. In a misjudgement, Ms Jackson made her first threat the day after the killing, at a time when sympathies were all with the star.Reuse content