Midfielder Cairney, 26, was arrested shortly after the incident in Queen Street on October 11 last year, and accused of hitting a man with a belt.
But after viewing CCTV footage, sheriff John Baird found Cairney was not guilty and branded the incident a "vicious and sustained attack" on him.
He told Cairney: "It's completely clear who the aggressor was in this situation and it certainly wasn't you."
The video showed Cairney being hit with a belt by a man described as 6ft 5in and 18st.
Cairney, from Livingston, said he was "pleased" the case was over.