Suphot Silarat and his twin brother Suphat received an original jail term of six months each before the court cited their guilty plea as grounds for leniency.
Suphot is a repeat offender, having violated the firearms law in 2010 and will therefore consecutively serve a previously suspended jail term of seven months. His combined imprisonment is 10 months.
The defence has applied for temporary release pending the appellate review, posting Bt100,000 bail for the two.
In its verdict, the court said the two had committed a premeditated attack against Worachet at Thammasat University.
Based on their confessions, the two held a grudge because Worachet aired his academic opinions on amending Article 112 of the Criminal Code, known as the lese majeste law.
The attack took place in the parking lot of the Tha Phrachan campus. The victim sustained a nosebleed and injuries to his right cheek bone and forehead.
The court said the two carried out the heinous attack without any respect for the law, therefore there was no cause to suspend the jail term.
The two pummelled Worachet in the face before fleeing on a motorcycle. They gave themselves up to police the following day.