Following the verdict, some 600 protesters marched through downtown St. Louis, chanting "No justice, no peace" and "Hey hey!"
The acting commissioner of police of the St. Louis Police Department, Lawrence O'Toole, said in a statement to the media late Friday night that his officers had responded to incidents in numerous locations in the city.
Two officers were taken to hospital after being hit by bricks when the demonstration turned violent, according to the city force. "But this is a protest that addresses injustices not only happening here in St Louis but around the country". "This violence won't be tolerated", Missouri Governor Eric Greitens said on Twitter.
"Orders to disperse were given numerous times".
Police said several protesters threw rocks and water bottles, while officers were seen in video footage and by eyewitnesses dousing at least five people with pepper spray about a block from the courthouse.
Former police officer Stockley was found not guilty of first-degree murder and armed critical action on Friday, nearly six years after the incident happened when he shot Smith five times after a high-speed auto chase that ended with a collision.
The reproduction of the story/photograph in any form will be liable for legal action. Approximately 1,000 people went to the mayor's house, where windows were broken, and police in riot gear fired tear gas into the crowd.
Protesters said the verdict highlighted racial injustice and a failure of the St Louis justice system and called for boycotts of St Louis businesses. Smith was eventually shot in his vehicle five times.
Former Officer Stockley had pleaded not guilty, saying he had acted in self defense during the December 2011 incident, while prosecutors had accused him of planting a gun on Smith to justify the shooting.