Illario Niko Johnson, who was arrested July 31, was the first to be rounded up following the event, according to Huntington Beach police. He was identified through social media, police said.
Johnson pleaded guilty to one felony count of arson of property, a misdemeanor count of participating in an unlawful assembly and a misdemeanor count of recklessly causing a fire to the property of another, according to court records.
Johnson must perform 50 hours of community service with the Glendale Fire Department and 150 more in another program that is approved by probation officials, said Deputy District Attorney Andrew Katz.
Johnson was also ordered to stay away from Main Street in Huntington Beach between Orange Avenue and Pacific Coast Highway, Katz said. Johnson was also placed on three years of informal probation.
About 250 officers from Huntington Beach and neighboring law enforcement agencies were brought in to control a mob after the surfing event.