Anthony wept after the clerk read the verdict, which jurors reached after less than 11 hours of deliberation over two days. The 25-year-old was charged with first-degree murder, which could have brought the death penalty if she had been convicted.
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Instead, she was convicted of only four counts of lying to investigators looking into the June 2008 disappearance of her daughter Caylee. Her body was found in the woods six months later and a medical examiner was never able to determine how she died.
Anthony will be sentenced by the judge on Thursday and could receive up to a year in jail for each lying count. Since she has been in jail since August 2008, she could walk free then.
After the verdict was read, Casey Anthony hugged her attorney Jose Baez and later mouthed the words "thank you" to him.
Prosecutors sat solemnly in their seats, looking stunned.
Prosecutor Jeff Ashton shook his head slightly from side to side in apparent disbelief. Across the room, Anthony's father wiped tears from his eyes. Without speaking to Casey, he and his wife left the courtroom escorted by police as the judge thanked the jury.
"While we're happy for Casey, there are no winners in this case," Baez said at a news conference afterward. "Caylee has passed on far, far too soon. And what my driving force has been for the last three years has been always to make sure that there has been justice for Caylee and Casey, because Casey did not murder Caylee. It's that simple."
He added: "This case has brought on new challenges of all of us. Challenges in the criminal justice system, challenges in the media, and I think we should all take this as an opportunity to learn and to realize that you cannot convict someone until they've had their day in court."
State Attorney Lamar Lawson thanked the prosecutors from his office who tried the case, and he said the case was never about the defendant.
"It has always been about seeking justice for Caylee and speaking on her behalf," he told reporters.
Jurors told the court that they didn't want to talk to the media at the courthouse.
Anthony's attorneys claimed that the toddler drowned accidentally in the family swimming pool, and that her seemingly carefree mother in fact was hiding emotional distress caused by sexual abuse from her father.
Prosecutors contended that Caylee was suffocated with duct tape by a mother who loved to party, tattooed herself with the Italian words for "beautiful life" in the month her daughter was missing and crafted elaborate lies to mislead everyone from investigators to her own parents.
Captivated observers camped outside the courthouse to jockey for coveted seats in the courtroom gallery, which occasionally led to fights among those desperate to watch the drama unfold.
Prior to the verdict on Tuesday, the judge said: "To those in the gallery please do not express any signs of approval or disapproval upon the reading of the verdict."
Anthony did not take the stand during the trial, which started in mid-May. Because the case got so much media attention in Orlando, jurors were brought in from the Tampa Bay area and sequestered for the entire trial.
Baez conceded that his client had told elaborate lies and invented imaginary friends and even a fake father for Caylee, but he said that doesn't mean she killed her daughter.
"They throw enough against the wall and see what sticks," Baez said of prosecutors during closing arguments. "That is what they're doing ... right down to the cause of death."
He tried to convince jurors that the toddler accidentally drowned in the family swimming pool and that when Anthony panicked, her father, a former police officer, decided to make the death look like a murder by putting duct tape on the girl's mouth and dumping the body in woods about a quarter-mile away.
Her father firmly denied both the cover-up and abuse claims. The prosecution called those claims "absurd," saying that no one makes an accident look like a murder.
Lead prosecutor Linda Drane Burdick concluded the state's case by showing the jury two side-by-side images. One showed Casey Anthony smiling and partying in a nightclub during the month Caylee was missing. The other was the tattoo she got a day before her family and law enforcement first learned of the child's disappearance.
"At the end of this case, all you have to ask yourself is whose life was better without Caylee?" Burdick asked. "This is your answer."
Prosecutors hammered on the lies Anthony, then 22, told from June 16, 2008, when her daughter was last seen, and a month later when sheriff's investigators were notified. Those include the single mother telling her parents she couldn't produce Caylee because the girl was with a nanny named Zanny -- a woman who doesn't exist; that she and her daughter were spending time in Jacksonville, Fla., with a rich boyfriend who doesn't exist; and that Zanny had been hospitalized after an out-of-town traffic crash and that they were spending time with her.
Among the trial spectators was 51-year-old Robin Wilkie, who said she has spent $3,000 on hotels and food since arriving June 10th from Lake Minnetonka, Minn. She tallied more than 100 hours standing in line to wait for tickets and got into the courtroom 15 times.
She said she's fascinated with the case because she is a victim of violent crime.
"True crime has become a unique genre of entertainment," Wilkie said. "Her (Casey's) stories are so extreme and fantastic it's hard to believe they're true but that's what engrosses people. This case has sex, lies and video tapes -- just like on reality TV."