“We the jury find George Zimmerman not guilty.”
The verdict looks set to polarise America as did the killing of the black teenager that led to the murder trial – and a nationwide debate over racial profiling and self-defence laws.
Jurors in Florida took 16 hours to acquit the white Hispanic neighbourhood watchman of all charges.
“I think the prosecution of George Zimmerman was disgraceful,” said defence lawyer Donald West. “I’m thrilled that this jury kept this tragedy from becoming a travesty.”
Trayvon Martin was unarmed when he was shot fatally in the chest.
But the defence claimed the 17-year-old had violently attacked Zimmerman and reached for his gun.
The “not guilty” verdict drew immediate protests outside the court in Sanford, the town where the fatal altercation happened.
“I think it’s outrageous, George Zimmerman is a cold-blooded murderer. He racially profiled Trayvon, he stalked him and he murdered him,” said a woman at the demonstration.
“My biggest disappointment is that the whole world knows that George Zimmerman committed a murder,” added a male protester.
Civil rights activist Jesse Jackson has appealed for people to remain calm. Initial protests elsewhere in the US have been small scale.
The National Association for the Advancement of Colored People said the case had re-energised the movement to end racial profiling.
Prosecutors claimed Zimmerman assumed from the teenager’s appearance that he was up to no good.
But Florida’s controversial “stand your ground” law allows people to use lethal force if they feel in imminent danger. Police cited the law in defending their decision not to arrest Zimmerman for weeks after the killing.
The political dimension of the case remains huge. After the teenager’s death, President Obama said if he had a son, “he would look like Trayvon”.