The officer was hit by the 16-year-old as he tried to prevent the teenager from assaulting the cartoonist at a lecture at Uppsala University last month.
"He was sentenced for violence against a state employee and an assault on a state employee," a court spokesperson at Uppsala in central Sweden told AFP.
The teenager was sentenced to 20 days community service and ordered to undergo a psychological assessment and pay damages of 500 kronor ($75) to the officer.
Vilks, whose caricature caused controversy in 2007, was punched in the head in a mass brawl as he delivered a lecture at the university on May 11th. Vilks' house in southern Sweden was the target of an arson attack on May 15th.
Lars Vilks courted global attention in 2007 when the Swedish regional daily Nerikes Allehanda published his satirical cartoon depicting Muhammad as a dog to illustrate an editorial on the importance of freedom of expression.
The cartoon prompted protests by Muslims in the town of Örebro in central Sweden, where the newspaper is based, while Egypt, Iran and Pakistan made formal complaints.
An Al-Qaeda front organisation then offered $100,000 to anyone who murdered Vilks - with an extra $50,000 if his throat was slit - and $50,000 for the death of Nerikes Allehanda editor-in-chief Ulf Johansson.
The protests in Sweden echoed the uproar in Denmark caused by the publication in September 2005 of 12 drawings focused on Islam, including one showing the prophet Muhammad with a turban in the shape of a bomb.
In March, US citizen Colleen LaRose, who called herself "JihadJane" in a YouTube video, was charged by US authorities with conspiring to kill Vilks after seven suspected co-plotters were arrested in Ireland.