The North Bangkok District Court initially sentenced Patharasak Thiamprasert to seven months in jail but it commuted the jail term by half after he pledged guilty.
The court also ordered the seizure of his pickup and the vocation of his driving license.
The case made headlines after a video clip taken by another driver went viral, showing Patharasak reversing his pickup to hit a Toyota car twice. Patharasak later gave an interview at the scene that the driver of the Toyata car hit his pickup after he refused to give way for the car to cut into his lane.
After the clip went viral, Patharasak admitted hitting the car during an interrogation by police. But when the case was filed against him in the court, he pledged innocence.
However, Patharasak made an about-face again Monday just before the court would deliver the ruling, pleading guilty.
The court ruled that Patharasak committed the crime in the broad daylight and in public place so the commuted jail term would not be suspended.
The incident caused Patharasak to be fired as a DJ of FM 89.5 Sweet FM radio station.
He was released on bail after deposited Bt15,000 as a guarantee, pending his plan to appeal to call for lighter sentence.